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IC 9081 



Bureau of Mines Information Circular/1986 



Thermodynamic Properties of Selected 
Metal Sulfates and Their Hydrates 



By Carroll W. DeKock 




UNITED STATES DEPARTMENT OF THE INTERIOR 



Information Circular 9081 

■ « 



Thermodynamic Properties of Selected 
Metal Sulfates and Their Hydrates 



By Carroll W. DeKock 




UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Hodel, Secretary 

BUREAU OF MINES 
Robert C. Horton, Director 




As the Nation's principal conservation agency, the Department of the Interior 
has responsibility for most of our nationally owned public lands and natural 
resources. This includes fostering the wisest use of our land and water re- 
sources, protecting our fish and wildlife, preserving the environmental and 
cultural values of our national parks and historical places, and providing for 
the enjoyment of life through outdoor recreation. The Department assesses 
our energy and mineral resources and works to assure that their development is 
in the best interests of all our people. The Department also has a major re- 
ibility for American Indian reservation communities and for people who 
Island Territories under U.S. administration. 






Library of Congress Cataloging in Publication Data*. 



DeKock, Carroll W 

Thermodynamic properties of selected metal sulfates and their 
hydrates. 

(Information circular / United States Department of the Interior, 
Bureau of Mines ; 9081) 

Bibliography: p. 55-59. 

Supt. of Docs, no.: I 28.27:9081. 

1. Transition metal compounds— Thermal properties. 2. Sulphates- 
Thermal properties. 3. Hydrates— Thermal properties. I. Title. II. 
Series: Information circular (United States. Bureau of Mines) ; 9081. 

TU295AJ4 [TN693.T7] 622s [549\75] 86-600060 



For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 



CONTENTS 



Page 



Abstract 1 

Unit of measure abbreviations and symbols used in this report 2 

Introduction 3 

Methods , conventions , and symbols 3 

Estimation procedure for hydrates 4 

Discussion of thermodynamic properties 4 

Ag 2 S0 4 . 4 

A1 2 (S0 4 )3 5 

A1 2 (S0 4 )3*6H 2 6 

BaS0 4 6 

BeS0 4 6 

BeS0 4 'H 2 f 7 

BeS0 4 «2H 2 and BeS0 4 '4H 2 7 

CaS0 4 r 7 

CaS0 4 «2H 2 0, CaS0 4 *l/2H 2 0(a), and CaS0 4 ' 1/2H 2 0( 3) 8 

CdS0 4 8 

CdS0 4 «H 2 and CdS0 4 *8/3H 2 8 

2CdO • CdS0 4 9 

Cs 2 S0 4 9 

In 2 (S0 4 ) 3 9 

K 2 S0 4 10 

KA1(S0 4 ) 2 10 

KA1(S0 4 ) 2 «12H 2 10 

Li 2 S0 4 10 

Li 2 So 4 " T 2 10 

MgS0 4 1 

MgS0 4 *H 2 1 

MgS0 4 «2H 2 and MgS0 4 *4H 2 1 

MgS0 4 -6H 2 1 

MgS0 4 '7Hi0 1 

Na 2 S0 4 1 

Na 2 S0 4 *7H 2 1 

Na 2 S0 4 *10H 2 12 

(NH 4 ) 2 S0 4 12 

NH 4 A1(S0 4 ) 2 12 

NH 4 A1(S0 4 ) 2 '12H 2 13 

PbS0 4 13 

Rb 2 S0 4 13 

T1 2 S0 4 14 

Zr(S0 4 ) 2 14 

Thermodynamic tables. — See following listing for specific pages. 

References 55 

THERMODYNAMIC TABLES 

Ag 2 S0 4 15 

A1 2 (S0 4 ) 3 16 

Al2(S0 4 ) 3 . 6H20 17 

BaS0 4 17 

BeS0 4 18 

BeS0 4 .H 2 20 

BeS0 4 * 2H 2 20 



11 

THERMODYNAMIC TABLE S— Continued 

Page 

BeS0 4 '4H 2 21 

CaS0 4 21 

CaS0 4 *2H 2 24 

CaS0 4 'l/2H20(a) 25 

CaS0 4 • 1/ 2H 2 0( 3 ) 25 

CdS0 4 26 

CdS0 4 'H 2 27 

CdS0 4 •8/3H 2 27 

2CdO«CdS0 4 28 

Cs 2 S0 4 29 

In 2 (S0 4 ) 3 31 

K 2 S0 4 32 

KA1( S0 4 ) 2 34 

KA1(S0 4 ) 2 '12H 2 0... 35 

Li 2 S0 4 36 

Li 2 S0 4 'H 2 0. . . . : 38 

MgS0 4 39 

MgS0 4 -H 2 42 

MgS0 4 -2H 2 43 

MgS0 4 '4H 2 43 

MgS0 4 »6H 2 44 

MgS0 4 '7H 2 44 

Na 2 S0 4 45 

Na 2 S0 4 • 10H 2 47 

(NH 4 ) 2 S0 4 47 

NH 4 A1(S0 4 ) 2 48 

NH 4 A1(S0 4 ) 2 *12H 2 48 

PbS0 4 49 

Rb 2 S0 4 50 

T1 2 S0 4 52 

Zr(S0 4 ) 2 53 



THERMODYNAMIC PROPERTIES OF SELECTED METAL SULFATES 

AND THEIR HYDRATES 

By Carroll W. DeKock ' 



ABSTRACT 

Thermodynamic data for selected metal sulfates were critically evaluated and 
compiled as part of the Bureau of Mines program to provide a scientific base for use 
in developing new technology and predicting the feasibility of new processes. Values 
for Cp°, S°, H° - H| 98 , -(G° - H| 98 )/T, AHf°, AGf°, and log Kf as functions of tem- 
perature are given in tabular form. 

Thermodynamic data were compiled for Ag 2 S0 4 , Al 2 (S0 4 )3, Al 2 (S0 4 ) 3 •6H 2 0, BaS0 4 , 
BeS0 4 , BeS0 4 '2H 2 0, BeS0 4 *4H 2 0, CaS0 4 , CaS0 4 '1/2H 2 0, CaS0 4 *2H 2 0, CdS0 4 , CdS0 4 «H 2 0, 
CdS0 4 »8/3H 2 0, 2CdO'CdS0 4 , Cs 2 S0 4 , In 2 (S0 4 ) 3 , K 2 S0 4 , KA1(S0 4 ) 2 , KA1(S0 4 ) 2 • 12H 2 0, 
Li 2 S0 4 , Li 2 S0 4 -H 2 0, MgS0 4 , MgS0 4 *H 2 0, MgS0 4 '2H 2 0, MgS0 4 '4H 2 0, MgS0 4 *6H 2 0, MgS0 4 »7H 2 0, 
Na 2 S0 4 , Na 2 S0 4 '7H 2 0, Na 2 S0 4 '10H 2 0, (NH 4 ) 2 S0 4 , NH 4 A1(S0 4 ) 2 , NH 4 A1(S0 4 ) 2 -12H 2 0, PbS0 4 , 
Rb 2 S0 4 , T1 2 S0 4 , and Zr(S0 4 ) 2 . 

1 Research chemist, Albany Research Center, Bureau of Mines, Albany, OR; faculty 
member, Oregon State University, Corvallis, OR. 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 

atm atmosphere (1 atm = 101,325 pascals) 

cal thermochemical calorie (1 cal = 4.1840 joules) 

cal/mol calorie per mole 

cal/ (mol »K) calorie per mole per kelvin 

K kelvin (the unit of thermodynamic temperature) 

kcal/mol kilocalorie per mole 

mol mole (gram formula weight or molar mass) 

mol pet mole percent 

Pa pascal 

OTHER ABBREVIATIONS AND SYMBOLS USED IN THIS REPORT 

° Standard state, pure phase at 1 atm 

C p Heat capacity at constant pressure 

F Faraday constant, 23,060.0 cal/(volt*equivalent) 

AG Gibbs energy change (AGf = Gibbs energy of formation) 

AH Enthalpy change (AHf = enthalpy of formation) 

H - H298 Enthalpy increment between T and 298.15 K 

H-298 ~ Ho Enthalpy increment between 298 and K 

Log K Logarithm (base 10) of the equilibrium coastant 

Log Kf Logarithm (base 10) of equilibrium constant of formation 

P Pressure in atmospheres, 1 atm = 101,325 Pa 

R Gas constant, 1.98719 cal/(mol«K) 

S Entropy 

T Thermodynamic temperature in kelvins 



INTRODUCTION 

As part of the Bureau of Mines effort to provide thermodynamic data for mineral 
technology advancement, thermodynamic properties of selected metal sulfates and their 
hydrates were critically evaluated and compiled. A 1982 publication compiled similar 
data on selected transition metal sulfates (11). 2 A number of early reviews of metal 
sulfates exist (29, _32,, 48). 

The data for the early reviews are often based on high-temperature sulfate de- 
composition data. The thermodynamic properties here are calculated on the basis of 
calorimetric data, many of which were unavailable for the early reviews. No review 
of the hydrated metal sulfates exists. 

This compilation has been prepared in the same format as Bureau of Mines Bulle- 
tin 672, "Thermodynamic Properties of the Elements and Oxides," by L. B. Pankratz 
(45). The values for the standard heat capacities (Cp), high-temperature relative 
enthalpies (H° - U^gg), enthalpies of formation (AHf°), and Gibbs energies of forma- 
tion (AGf°) are given in tabular form. The tables include Gibbs energy functions, 
-(G° - H298)/T, and logarithms (base 10) of the equilibrium constants of formation, 
log Kf . 

Where possible, all phases of an element or compound are presented in a single 
table. Temperatures of transformations and thermodynamic properties at these temper- 
atures are included in the table. Immediately below the table, the nature of these 
transformations is given, along with their associated enthalpies. All thermodynamic 
values for the elements are from Pankratz (45). 

METHODS, CONVENTIONS, AND SYMBOLS 

The values in this compilation are the result of a review and critical evalua- 
tion of relevant thermodynamic data through July 1984. Standard enthalpies of forma- 
tion at 298.15 K are corrected to the latest CODATA (7) values where the accuracy of 
the original data warrants such care. The CODATA value for the standard enthalpy of 
formation of S0|"(aq) at infinite dilution is the major correction for this document. 
CODATA gives AHf°(S0|-, »aq) = -217.4 kcal/mol, while Wagman (63) reports AHf°(S0|-, 
o>aq) = -217.32 kcal/mol. Sulfate ion corrections in this document are based on the 
CODATA value. Also, AHf°(H 2 0,Jl) = -68.315 kcal/mol, used throughout this review, is 
from Wagman (63). 

The selected experimental data were fitted to a polynomial in terms of tempera- 
ture by using a modified form of the computer program described by Justice (28). 
This program, along with a plot of function (H° - H.2 98 )/(T - 298.15), which takes 
a known value of Cp° at 298.15 K, was used to merge high-temperature data smoothly 
with low-temperature heat capacity data. The resulting polynomial was then used in 
a subroutine of the program to calculate standard heat capacities, relative enthal- 
pies, Gibbs energy functions, and standard entropies at selected temperatures. In 
addition, the thermodynamic tables include values for the standard enthalpy of 

^Underlined numbers in parentheses refer to items in the list of references at the 
end of this report. 



formation, Gibbs energy of formation, and the logarithm of the equilibrium constant 
of formation. Tabulated values are given for the substances in their standard states 
(indicated by the superscript "°"). 

Sources of data used in this compilation are given in the list of references; 
additional sources reviewed and considered less reliable are not included. Estimates 
are used where the necessary data were lacking, as explained in the section on esti- 
mation procedures. Estimated and extrapolated values are indicated in the note below 
each table. 

The common practice of tabulating five- and sometimes six-digit values has been 
followed. For example, enthalpy values are given to the nearest calorie. The number 
of digits given is not intended to reflect the accuracy of the experimental values 
used, but rather to produce internal consistency in the tables. In the text, values 
are given to the significant figures to which they are thought to be accurate. 

ESTIMATION PROCEDURES FOR HYDRATES 

The same estimation procedures were used as in the first compilation in this se- 
ries (11) for hydrates for which data were unknown. Briefly, the estimation methods 
are as follows: Heat capacities for hydrates were estimated by adding 9.3 cal/ 
(mol»K) per mole H 2 to the heat capacity of the anhydrous compound to obtain the 
heat capacity at 298.15 K. The entropy of the hydrates at 298.15 K was estimated by 
adding 9.5 cal/(mol»K) per mole H 2 to the entropy of the anhydrous compound at 
298.15 K. Other estimation procedures, tailored for individual compounds, are dis- 
cussed in the text. 

With the values at 298.15 K in hand, it was then necessary to estimate the heat 
capacities above 298.15 K. For hydrates for which low-temperature data are avail- 
able, heat capacities up to 550 K were estimated by extrapolating the low-temperature 
data, using a least-squares fit with the quadratic equation, Cp = a + bT + cT 2 . For 
salts for which data are not available, high-temperature heat capacities were esti- 
mated using the following equation: 

Cp(T) = Cp(298.15) + b(T-298.15), 

where b is a coefficient dependent on n, the number of water molecules. The values 
calculated for b are — 



1 


0.09 


2 


.10 


3 


.132 


4 


.144 



5 


0.180 


6 


.216 


7 


.252 



DISCUSSION OF THERMODYNAMIC PROPERTIES 

Ag 2 S0 4 (c) 

The values from Parker ( 50 ) for the enthalpy of formation and entropy at 
298.15 K are adopted. 



Ag 2 S0 4 exists in the orthorhombic form at ambient temperature and transforms to 
the Na 2 S0 4 (I) structure at 698.6 K ( 27 , 42). Low-temperature heat capacity values 
have been measured by Latimer (40). Heat capacity values measured by Shmidt (57) 
from 299.2 to 727.6 K using an adiabatic calorimeter were merged with the low-tempeir- 
ture values of Latimer (40). Conard (9) measured high-temperature enthalpy values 
over the range 568 to 1,025 K using a drop calorimeter. The results of Conard do not 
merge well with those of Shmidt (57). Also the values of Conard scatter badly. For 
these reasons the values of Shmidt ( 57 ) for the transition enthalpy and temperature 
were adopted. Shmidt determined the transition temperature to be 698.6 K with an 
enthalpy of transition equal to 3.901 kcal/mol. An enthalpy of transition equal to 
3.8 kcal/mol and a transition temperature of 700 K were determined in this laboratory 
by differential scanning calorimetry. 3 These values are in good agreement with those 
of other workers using differential thermal analysis. Hedvall (25) observed a tran- 
sition enthalpy of 3.8 kcal/mol. Others (9_, 25 ) have reported a transition tempera- 
ture of 703 K. 

Conard (9) found a melting point of 926 K with an enthalpy of fusion equal to 
4.56 kcal/mol. These values are adopted here. Their average heat capacity value for 
the liquid was 35 cal/(mol*K), which is the adopted value. 

Al 2 (S0 4 ) 3 (c) 

Low-temperature heat capacity data are given by Shomate (58) from 54.7 to 
296.2 K. An excellent fit of these data was obtained using the appropriate polyno- 
mial equations from which the entropy and enthalpy over the range 53 to 298.15 K were 
obtained. The entropy and enthalpy from to 53 K were obtained from the function 
sum given by Shomate (58) to represent the heat capacities over the entire tempera- 
ture range: 

D(155.7/T) + 3E(238/T) + 6E(528/T) + 6E(1,194/T). 

The symbols D and E denote, respectively, Debye and Einstein functions. There 
is excellent agreement between the present data analysis and that of Shomate (58), as 
shown below for entropies at 298.15 K for A1 2 (S0 4 )3: 

Shomate This wor k 

to 53 K 3.76 3.77 

53 to 298.15 K 53.43 53.45 

S°(298.15) 57.19 57.22 

The above entropy values at 298.15 K are both rounded to 57.2 cal/(mol«K). 

The high-temperature enthalpy values were taken from Shomate (59). 

The standard enthalpy of formation at 298.15 K is from Wagman (63) , corrected 
for the enthalpy of formation of the sulfate ion at infinite dilution. 

3 The author thanks Robert R. Brown, research chemist, Albany Research Center, Al- 
bany, OR 97321, for performing the differential scanning calorimeter measurements on 
various compounds. 



Al 2 (S0 4 )3-6H 2 0(c) 

Low-temperature heat capacities are given by She-mate ( 58 ) from 54.5 to 296.1 K. 
An excellent fit of these data was obtained using the appropriate polynomial equa- 
tions from which the entropy and enthalpy over the range 53 ro 298.15 K were obtained 
from the computer subroutine programs. The entropy and enthalpy from to 53 K were 
obtained from the function sum given by Shomate to represent the heat capacities over 
the entire temperature range: 

D(78.9/T) + 3E(142.5/T) + 8E(340/T) + 16E(872/T). 

Good agreement exists between the present data analysis and that of Shomate as 
shown below for entropies at 298.15 K for A1 2 (S0 4 ) 3 *6H 2 0: 

Shomate This work 

to 53 K... 11.23 11.24 

53 to 298.15 K 100.88 100.95 

S°(298.15) 112.09 112.19 

Accordingly 112.2 cal/(mol*K) was added as the entropy at 298.15 K. 

The high-temperature enthalpy values were obtained by extrapolating the low- 
temperature data between 206.2 to 296.5 K using a quadratic polynomial. 

The standard enthalpy of formation at 298.15 K is from Wagman (63) , corrected 
for the enthalpy of formation of the sulfate ion at infinite dilution. 

BaS0 4 (c) 

Parker's ( 49 ) enthalpy of formation for BaS0 4 (c), after correction for the 
enthalpy of formation of the sulfate ion at infinite dilution, was adopted. The 
entropy of BaS0 4 (c) at 298.15 K was recalculated from the low-temperature heat 
capacity data of Latimer (39). Latimer estimated the entropy at 20 K to be 0.379 
cal/(mol*K), which is adopted here, and calculated S 298 [BaS0 4 (c) ] = 31.5 cal/(mol*K). 
Recalculation of the data gave S 298 [BaS0 4 (c) ] = 31.6 cal/(mol»K), which is the value 
reported by Parker (49). This evaluation also gave [H 298 - H ° ] = 4.584 kcal/mol. 

The only high-temperature enthalpy study is that of Lashchenko (36) over the 
range 293 to 1,323 K. These data were only used above 600 K because the lower tem- 
perature data had severe scatter. The low-temperature heat capacity data of Latimer 
(39) were extrapolated to 500 K and joined smoothly with the high-temperature data. 

BeS0 4 (c) 

Navratil (44) determined the enthalpy of formation of BeS0 4 (c) by sulfuric acid 
solution calorimetry. The value was obtained in a careful study that involved three 
separate Be samples and two different sulfuric acid solutions. Recalculated using 
the CODATA (7) S0|~ value, the Navratil value yields AHf 298 [BeS0 4 (c) ] = -287.08 
kcal/mol. This value is adopted. The value in Parker (48) for AHf 298 [BeS0 4 (c) ] is 
-288.05 kcal/mol. Low-temperature heat capacity values, high-temperature enthalpies, 
and the entropy at 298.15 K were those adopted by JANAF (15). 



BeS0 4 'H 2 0(c) 

From a study of the vapor pressure of BeS0 4 (c) + H 2 Q, Broers (_5-j>) determined 
AH°(298.15 K) = 16.27 kcal/mol for the reaction BeS0 4 «H 2 0(c) = BeS0 4 (c) +H 2 0(g). 
Using the adopted AH values for BeS0 4 (c) and H 2 0(g) gives AHf 298 [BeS0 4 *H 2 0(c) ] 
= -361.15 kcal/mol. This value is adopted. Parker (49) gives AHf 298 [BeS0 4 'H 2 0] 
= -364.2 kcal/mol. Broers (.5-6) also obtained S 298 [BeS0 4 'H 2 0] = 28.91 cal/(mol»K) 
and estimated C° = 28.56 cal/(mol*K). These values are adopted. The high-temper- 
ature heat capacity dependence was estimated as discussed earlier. 

BeS0 4 «2H 2 0(c) and BeS0 4 '4H 2 0(c) 

Navratil (44) recalculated the enthalpies of formation for BeS0 4 *2H 2 0(c) and 
BeS0 4 •4H 2 0(c) obtained by Taylor (62) in the study of the enthalpies of formation of 
BeS0 4 (c) and the respective hydrates. After correction for the enthalpy of formation 
for S0^ _ Navratil' s (44) recalculated values are AHf 298 [BeS0 4 «2H 2 0(c) ] = -434.78 
kcal/mol and AHf 298 [BeS0 4 *4H 2 0(c) ] = -578.38 kcal/mol. These values are adopted. 
Parker (49) gives AHf 298 [BeS0 4 -2H 2 0] = -435.74 kcal/mol and AHf 298 [BeS0 4 '4H 2 0] 
= -579.29 kcal/mol. Low-temperature heat capacity values and entropy values are 
taken from Gardner (23). High-temperature heat capacities were obtained by extrapo- 
lation of the low-temperature values. 

CaS0 4 (c) 

There are three recognized forms of anhydrous calcium, sulfate: insoluble anhy- 
drite, (i), and two forms of soluble anhydrite, (a) and (3). The enthalpies of for- 
mation for all three forms are taken from Parker (49) after correction for the en- 
thalpy of formation of the sulfate ion. 

All entropy values were reevaluated using the low-temperature heat capacity data 
of Kelley (31). Debye-Einstein function sums are given by Kelley for each form of 
anhydrous CaS0 4 . These were used to extrapolate the entropy and enthalpy from K to 
approximately 50 K. The function sums for each of the forms are — 

CaS0 4 (i): D(208/T) + 2E(300/T) + 2E(815/T) 

CaS0 4 (ct): D(217/T) + 2E(278/T) + 2E(821/T) 

CaS0 4 (g): D(286/T) + 2E(246/T) + 2E(844/T) 

The calculated entropy values are compared below with those reported by Kelley. 

CaS0 4 (i) CaS0 4 (q) CaS0 4 (g ) 
S° (50.1) (Kelley) 

S°(50.1)(This work) 

S°(298) - S°(50.1)(Kelley) 

S°(298) - S°(50.1)(This work) 

S°(298)(Kelley) 

S°(298)(This work) 



1.51 


1.76 


1.57 


1.655 


1.89 


1.48 


23.95 


24.17 


24.33 


23.96 


24.16 


24.24 


25.5 


25.93 


25.90 


25.62 


26.05 


25.72 



It is clear from the above tabulation that the entropy calculated by either 
method is in good agreement between 50.1 and 298.15 K for both CaS0 4 (i) and CaS0 4 (a). 
For CaS0 4 (g) a difference of 0.09 cal/(mol»K) exists is this region. This is very 
good considering the method of calculation, i.e. , Kelley determined the entropy by a 
graphical method, while in this work the entropy is determined by a least-squares 
analytical fit of the heat capacity data with a subsequent subroutine generating en- 
tropy. Kelley's (31) De bye-Einstein functions were used for the extrapolation from 
to 50.1 K, yet in all cases the two sets differ by 0.1 cal/(mol # K) in an apparently 
random manner. In this work the value of the entropy calculated from the Debye- 
Einstein functions from to 50.1 K was determined using a computer program that had 
been carefully checked against other data. At present it is uncertain why Kelley's 
(31) extrapolated values differ so significantly from those reported here. 

The high-temperature enthalpy values for all three forms were taken from Lash- 
chenko (37-38). The data scatter badly at the lower temperatures. Accordingly, some 
of the lower values were deleted in the analysis. 

CaS0 4 «2H 2 0(c), CaS0 4 * l/2H 2 0(a,c) , and CaS0 4 •l/2H 2 0(e ,c) 

Three hydrates of calcium sulfate are considered here: CaS0 4 *2H 2 0(c) , CaS0 4 
•l/2H 2 0(a,c), and CaS0 4 »l/2H 2 0(3 ,c) . 

The definitive work on the hydrates of calcium sulfate still remains that of 
Kelley published in 1941 (31). The enthalpies of formation and entropies at 298.15 K 
for all the compounds were taken from Parker (49). Heat capacity values were extrap- 
olated to 550 K by the methods discussed in the introduction, using the heat capacity 
data from Kelley (31) for the hemihydrates and the data from Latimer (39) for the di- 
hydrate. The data below 298.15 K for the dihydrate were obtained by fitting the heat 
capacity data of Latimer ( 39 ) to a polynomial and calculating the entropy and enthal- 
py at the temperatures of interest. The fit in the present work yielded S°(298) 
- S°(19.95) = 46.062 cal/(mol*K), while the entropy reported by Latimer ( 39 ) over the 
same temperature interval was 46.096 cal/(mol # K) obtained by a graphical method. 

CdS0 4 (c) 

Adami (JL_) found the enthalpy of the reaction 

CdO(c) + H 2 SO 4 '7.068H 2 O(l) = CdS0 4 (c) + 8.068 H 2 0(1) 

to be AH = -20.140 kcal by hydrochloric acid solution calorimetry. CODATA (_7_) re- 
ports AHf 298 [CdO(c)] = -61.7 kcal/mol. Wagman ( 63 ) gives AHf 298 [H 2 S0 4 '7.068H2O] 
= -209.566 kcal/mol after making the sulfate correction. These values give 
AHf 298[CdS0 4 (c) ] = -223.09 kcal/mol, which is the adopted value. Low-temperature 
(15.22 to 312.81 K) heat capacities and entropies are those reported by Papadopoulos 
(47). No high-temperature enthalpy data are available; however, the data were esti- 
mated above 300 K using the high-temperature enthalpy data for ZnS0 4 (c) (11). 

CdS0 4 'H 2 0(c) and CdS0 4 -8/3H 2 0(c) 

The enthalpies of formation for both CdS0 4 *H 2 and CdS0 4 # 8/3H 2 were taken from 
Wagman (63) after making the sulfate correction. Heat capacities (15 to 300 K) and 
entropies are from Papadopoulos (47). High-temperature data were estimated by ex- 
trapolating the low-temperature heat capacities to 550 K. 



2CdO'CdS0 4 (c) 

Beyer (j4) measured the heat capacity of cadmium oxy sulfate, 2Cd0*CdS0 4 , from 
5.16 to 300.7 K by adiabatic calorimetry. The relative enthalpy was measured to 
1,001.5 K by copper-block drop calorimetry. A nonisothermal transition was observed 
over the temperature range 245 to 260 K with a peak at 253 K. The value at 298.15 K 
for [H? - H°] = 8.604 kcal/mol. 

Ko (33), using HC1 solution calorimetry, found AHf 298 [2CdO»CdS0 4 (c) ] = -345.70 
kcal/mol. This value is adopted. This is to be compared with Schaefer (55) , who 
calculated a third-law value from electrochemical cell measurements, AHf 2g8 [2Cd0 
•CdS0 4 (c)] = -344.4 kcal/mol, in good agreement with the value reported by Ko (33). 

Cs 2 S0 4 (c) 

The enthalpy of formation, AHf 298 [Cs 2 S0 4 ] = -344.97 kcal/mol, is from Wagman 
( 65 ) after correction for the enthalpy of formation of the sulfate ion at infinite 
dilution. 

The low-temperature heat capacities of Cs 2 S0 4 were measured by Paukov (51) over 
the range 12.82 to 308.72 K. The adopted value for S| 98 = 50.64 cal/(mol*K) and the 
value for [H 2 9 8 - H°] = 6.628 kcal are those reported by JANAF ( 18 ) in their evalua- 
tion of Paukov' s ( 51 ) data. High-temperature heat capacities have been measured by 
Shmidt (56) over the range 297.5 to 774.0 K. Denielou (12-14) carried out high- 
temperature enthalpy measurements by drop calorimetry over the range 400 to 910 K. 
The low-temperature heat capacities of Paukov ( 51 ) were joined with the high-temper- 
ature heat capacities of Shmidt (56) to provide enthalpy values which were merged 
with the enthalpy values of Denielou (12-14) above 700 K. 

JANAF (18) adopted a transition temperature of 940 K with an enthalpy of transi- 
tion of 1.030 kcal/mol, based on the difference between the smooth enthalpy curves of 
the high- and low-temperature modifications. A transition temperature of 997 K and 
an enthalpy of transition value of 0.072 kcal/mol were determined in this laboratory 
by differential scanning calorimetry. The present work adopts the latter values for 
the enthalpy and temperature of transition for Cs 2 S0 4 . This transition is very simi- 
lar to that for Rb 2 S0 4 . See the discussion of the Rb 2 S0 4 system. 

The melting point is that adopted by JANAF ( 18 ) at 1,278 K, and the enthalpy of 
fusion is calculated to be 8.47 kcal/mol from the difference in the smoothed enthalpy 
curves between the liquid and the solid forms. 

In 2 (S0 4 ) 3 (c) 

Barany (2) determined the enthalpy of formation to be AHf 298 [In 2 (S0 4 ) 3 (c) ] 
= -651.34 kcal/mol, using solution calorimetry. This value includes the correction 
for the enthalpy of formation of the sulfate ion. 

Low-temperature heat capacity data for anhydrous indium sulfate were reported 
by Pankratz (46) from 52 to 296 K. A reevaluation of these data, including a recal- 
culation of the De bye-Einstein function sums, yielded S 298 [In 2 (S0 4 ) 3 ] = 72.24 cal/ 
(mol'K). This is good agreement with Pankratz's analysis, which yielded 72.2 
cal/(mol«K). 



10 

High-temperature enthalpies were also obtained from Pankratz (46). An excellent 
fit between low- and high-temperature heat capacities were observed. 

K 2 S0 4 (c) 

All data for K 2 S0 4 are taken from JANAF (16). 

KAl(S0 4 ) 2 (c) 

Wagman ( 65 ) reported AHf 298 [KAl(S0 4 ) 2 (c) ] = -590.56 kcal/mol after correction 
for the enthalpy of formation of the sulfate ion. This value is adopted. A recalcu- 
lation of the data from Kelley (30) yielded AHf 298 [KAl(S0 4 ) 2 (c) ] = -590.46 kcal/mol, 
in good agreement with the value reported by Wagman (65). 

Low-temperature heat capacity values were reported by Kelley ( 30 ) in the range 
54.6 to 296.5 K. These data were reevaluated, including a recalculation of the 
De bye-Einstein function sums, to obtain S 298 [KAl(S0 4 ) 2 (c) ] = 48.94 cal/(mol'K). Kel- 
ley 's (30) analysis yielded S 298 [KAl(S0 4 ) 2 (c) ] = 48.9; Wagman (65) also reports 
S 298 [KAl(S0 4 ) 2 (c)] = 48.9 cal/(mol*K). 

A smooth fit between the low- and high-temperature heat capacity data was ob- 
tained by giving a weight of zero to the 368.5 K point reported by Kelley (30). 
High-temperature heat capacities and entropies were calculated from a smooth fit of 
the remaining high-temperature enthalpy data (30). 

KAl(S0 4 ) 2 -12H 2 0(c) 

The enthalpy of formation reported by Wagman (65) is AHf 298 [KA1(S0 4 ) 2 * 12H 2 0(c) ] 
= -1,448.96 kcal/mol after correction for the enthalpy of formation of the sulfate 
ion. This value is identical to that obtained from Kelley (30) using values from the 
present work for the enthalpy of formation of K 2 S0 4 and Al 2 (S0 4 ) 5 *6H 2 0, together with 
the accepted value for the enthalpy of formation of water. 

The entropy at 298.15 K is from Wagmen (65). Low-temperature heat capacities 
from Shomate ( 58 ) were matched with the heat capacities reported by Gronvold (24) in 
the region 298.15 to 358.99 K. 

The transition enthalpy for KA1(S0 4 ) 2 •12H 2 0(c) to KA1(S0 4 ) 2 »3H 2 plus aqueous 
solution at 358.99 K is reported by Gronvold (24) to be 22.8 kcal.mol. 

Li 2 S0 4 (c) 

All data for Li 2 S0 4 (c) are taken from JANAF (17). 

Li 2 S0 4 »H 2 0(c) 

The enthalpy of formation of Li 2 S0 4 *H 2 0(c) was determined by Barany (_3) using 
hydrochloric acid solution calorimetry. Recalculation of the results using auxiliary 
data from CODATA (_7) and Wagman (63) yields AHf 298 [Li 2 S0 4 *H 2 0] = -414.53 kcal. This 
value is adopted. Low-temperature heat capacities have been measured by Paukov (53) 
from 13.87 to 300.74 K. Paukov's calculated value for S 298 is 34.995 cal/(mol«K), 
which is adopted here. The value reported by Wagman (65) , 39.1 cal/(mol*K), appears 
to be in error. The heat capacity values above 298.15 K were obtained by extrapola- 
tion of the low-temperature values of Paukov (53). 



11 

MgS0 4 (c) 

Until recently, the enthalpy of formation values for MgS0 4 (c) were quite uncer- 
tain. For example, JANAF (15) selected AHf 2 98[MgS0 4 (c) ] = -301.6 kcal/mol, while 
Parker (49) gave -307.1 kcal7mol; other values reported were -313.0 kcal/mol by Kel- 
ley (29) and -310.0 kcal/mol by Lau (41) . MgS0 4 (c) exists in two orthorhombic crys- 
talline forms, MgS0 4 (a) and MgS0 4 (3) (80. The above-reported values for the enthalpy 
of formation make no reference to the crystalline form of MgS0 4 . In an effort to 
clarify the enthalpy of formation value for MgS0 4 , Ko ( 34 ) prepared both forms of 
MgS0 4 and determined their enthalpies of formation by hydrochloric acid solution cal- 
orimetry. The values are AHf ^ 98 [MgS0 4 (a) ] = -308.03 kcal/mol and AHf | 98 [MgS0 4 (3)] 
= -307.11 kcal/mol after correcting for the enthalpy of formation of the sulfate 
ion. Heat capacities, entropies, and high-temperature enthalpies are taken from 
JANAF (15). 

MgS0 4 -H 2 0(c) 

Correcting the value of Ko (34) for the enthalpy of formation of the sulfate ion 
yields AHf 298 [MgS0 4 *H 2 0(c) ] = -384.80 kcal/mol. This value was determined in the 
same study as the above values for a- and 3 _ MgS0 4 (c). The heat capacity at 9° C was 
determined by Rolla (54) to be 33.2 cal/(mol*K). The heat capacity values in the 
MgS0 4 *H 2 table are estimates based on the value by Rolla. The entropy at 298.15 K 
is from Parker (49) . 

MgS0 4 «2H 2 0(c) and MgS0 4 »4H 2 0(c) 

The enthalpies of formation are from Parker (49) after making the SOf" correc- 
tion, while the heat capacities and entropies are estimates. The enthalpy of forma- 
tion, AHf 2 9s[MgS0 4 # 2H 2 0(c) ] = -453.3 kcal/mol, appears to be too positive for the 
required stability of the dihydrate with respect to the monohydrate. 

MgS0 4 «6H 2 0(c) 

The enthalpy of formation is from Parker ( 49 ) after making the S0|~ correction, 
while the low-temperature heat capacities and entropy values are from Cox ( 10 ) . The 
heat capacity values above 320 K were obtained by extrapolation of the low- 
temperature values . 

MgS0 4 -7H 2 0(c) 

The enthalpy of formation at 298.15 K after making the S0|~ correction and en- 
tropy at 298.15 K are from Parker (49) . The heat capacity at 9° C was determined by 
Rolla (54) , and the heat capacity values given in the MgS0 4 *7H 2 table are estimates 
based on their value. 

Na 2 S0 4 (c) 

All data for Na 2 S0 4 (c) are taken from JANAF (16). 

Na 2 S0 4 -7H 2 0(c) 

Gans (22) , from equilibrium vapor pressure measurements, has established the 
existence of the heptahydrate as an independent stable phase. The upper temper- 
ature limit for coexistence with the saturated aqueous solution is 296.61 K for the 



12 

heptahydrate. Gans values are AHf 2 98[Na 2 S0 4 *7H 2 0] = -826.96 kcal/mol and 
S| 98 [Na 2 S04-7H 2 0] = 98.47 cal/(mol*K). 

Na 2 S0 4 »10H 2 0(c) 

The enthalpy of formation, after the sulfate correction, and entropy are taken 
from Wagman (65). The temperature dependence of the heat capacity was estimated us- 
ing the method discussed in the introduction. Gronvold (24) reported that the peri- 
tectic transition to Na 2 S0 4 (c) and aqueous solution occurs at 305.533 K with an en- 
thalpy of 18.65 kcal/mol. 

(NH 4 ) 2 S0 4 (c) 

The enthalpy of formation is from Parker ( 50 ) after making the S0|" correction. 

The low-temperature heat capacity values from 52.7 to 295.4 K and high-temper- 
ature enthalpies from 402 to 640 K were reported by Kelley ( 30 ) . 

The entropy at 298.15 K was recalculated from the low-temperature heat capacity 
data (30) . TheDebye-Einstein function sum given by Kelley ( 30 ) for (NH 4 ) 2 S0 4 (c) up 
to 150 K is 

D(121.7/T) + 2E(201/T) + 4E(472/T) + 8E(1,090/T). 

This function sum gave S°(50.12) = 4.58 cal/(mol*K). The data from 50.12 to 
190 K were fit with a polynomial, which resulted in an entropy of 26.71 cal/(mol«K) 
in this region. Kelley ( 30 ) reports a transition at 233.4 K with an entropy change 
of 10.47 cal/(mol*K) in the region 190 to 230 K. The data from 230 to 298.15 K were 
fit with a polynomial, yielding an entropy change of 10.95 cal/(mol*K) in this inter- 
val. The total yields S 2 98 = 52.71 cal/(mol # K), which is the adopted value. This 
value is also reported by Parker (50) . This compares with S 298 = 52.6±0.3 cal/ 
(mol*K) reported by Kelley (30) from analysis of the same data. 

The slopes of the low-temperature heat capacity data and the heat capacities ob- 
tained from the high-temperature enthalpy data did not match smoothly. A good match 
was obtained by eli.minating the points at 402.1 K and 639.6 K and weighting the low- 
temperature data appropriately. 

NH 4 Al(S0 4 ) 2 (c) 

The enthalpy of formation of NH 4 A1(S0 4 ) 2 is reported by Wagman (63) , after mak- 
ing the sulfate correction, to be AHf 2 93[NH 4 A1(S0 4 ) 2 ] = -562.36 kcal/mol. Kelley 
(30) reports AHf 2 98[(NH 4 )A1S0 4 ) 2 ] = -561.15 kcal/mol, which was recalculated using 
our adopted values for enthalpy of formation of (NH 4 ) 2 S0 4 and A1 2 (S0 4 ) 3 , 6H 2 0, giving 
a value of AHf 298 [NH 4 A1(S0 4 ) 2 ] = -562.46 kcal/mol. The average of these two, -562.4 
kcal/mol, is adopted. 

Low-temperature heat capacity values from 54.7 to 296.2 K are reported by Kelley 
(30) . High-temperature enthalpy measurements from 377.9 to 698.7 K are also reported 
by Kelley (30). 

The entropy at 298.15 K was recalculated on the basis of the low-temperature 
heat capacity data of Kelley (30) . The Debye-Einstein function sum given by ( 30 ) for 
NH 4 A1(S0 4 ) 2 is 



13 

D(165.2/T) + 3E(248/T) + 5E(538/T) + 5E(1,216/T). 

This function sum gave S°(53.09) = 3.39 cal/(mol»K), very close to Kelley's 3.37 
cal/(mol*K) (30) . The recalculated entropy is S| 98 = 51.71 cal/(mol°K), which is 
identical with - " that reported by Kelley (30) . The above evaluation also gave [H 298 

- H°] = 8.629 kcal/mol at 298.15 K. 

NH 4 Al(S0 4 ) 2 -12H 2 0(c) 

The enthalpy of formation, AHf 298 [NH 4 A1(S0 4 ) 2 ' 12H 2 0(c) ] = -1,420.42 kcal/mol, is 
from Wagman ( 63 ) , corrected for the enthalpy of formation of the sulfate ion. This 
value compares - well with AHf ° [NH 4 A1(S0 4 ) 2 «12H 2 0] = -1,420.59 kcal/mol, which is based 
on a recalculation of the data given in Kelley ( 30 ) . 

The heat capacity values are from Gronvold (24) merged with values to 
296 K from Kelley ( 30 ) . Gronvold ( 24 ) also reports that the enthalpy of fusion of 
NH 4 Al(S0 4 )-12H 2 0(c) at 367.13 K is 29.16 kcal/mol. 

The entropy at 298.15 K is from Wagman (63). 

PbS0 4 (c) 

The enthalpy of formation and entropy at 298.15 K are from CODATA (7). H 298 

- Hq is also taken from CODATA (7_) . High-temperature enthalpy values were taken from 
data by Krestovnikov (35) , who obtained data over the range 288 to 1,073 K by drop 
calorimetry. Krestovnikov 's values were fit smoothly to the low-temperature heat ca- 
pacity data of Gallagher ( 21 ) . 

Comparison of log Kf values for PbS0 4 obtained from solid state emf determina- 
tions by Fredriksson (20) show close correspondence between the calculated and exper- 
imental values : 

log Kf(PbS0 4 ) 
T/K Ref(20) This work 

1,000 28.43 28.51 

1,100 23.95 23.91 

It is gratifying to see this close correlation between data arrived at by calorimet- 
ric measurements (our calculations) and emf high-temperature measurements (20). 

Rb 2 S0 4 (c) 

The enthalpy of formation AHf 2 98 [Rb 2 S0 4 ] = -343.12 kcal/mol is from CODATA (7). 

The low-temperature heat capacity from 12.54 to 303.12 K was measured by Paukov 
(52). Paukov's calculated entropy at 298.15 K is S 298 [Rb 2 S0 4 ] = 47.19 cal/(mol«K), 
which is adopted here. High-temperature heat capacities from 298.15 to 770.5 K have 
been measured by Shmidt (56) , while Denielou (12-14) has measured the high-temper- 
ature enthalpy from 274 to 1,466 K. Both Ingraham (26) and Denielou (12-14) report a 
first-order transition at 931 K with transition enthalpies of 2.11 kcaTTmol and 1.039 
kcal/mol, respectively. The enthalpy of transition was measured in this laboratory 
by differential scanning calorimetry (DCS) and found to be far smaller than orig- 
inally reported. The measured value is 0.104±0.01 kcal/mol in the region 925 to 



14 

938 K. The DSC data show an anomalous increase in the heat capacity beginning at 
about 825 K with a very small first-order component at 931 K. The data of Denielou 
(12-14) show this anomalous effect, which they ignored in their interpretation. The 
same effect is noted for Cs 2 S0 4 . 

The low-temperature data of Paukov (52) were smoothly merged with the high- 
temperature data of Shmidt (56) by fitting the data to orthogonal polynomials. The 
data of Denielou (12-14) were not used in the region 298 to 770 K because they did 
not merge well with the low-temperature data of Paukov ( 52 ) . The enthalpy data of 
Denielou (12-14) above 770 K, however, were merged with the data of Shmidt ( 56 ) to 
obtain the enthalpy to 931 K. Above 931 K, the data of Denielou (12-14) were avail- 
able. The data in the liquid region were smoothly extrapolated to 2,000 K using 
a heat capacity for the liquid of 49.33 cal/(mol*K). The enthalpy of fusion AH^ 
= 9.180 kcal/mol is adopted from Denielou (12-14) . Our enthalpy values in the region 
above 931 K were identical to those of Denielou (12-14) . 

Tl 2 S0 4 (c) 

The entropy and enthalpy of formation at 298.15 K are from Wagman ( 63 ) after 
correction for the enthalpy of formation of the sulfate ion. Shmidt ( 57 ) measured 
the heat capacity of TI2SO4 using an adiabatic calorimeter over the temperature range 
298.4 to 582.8 K. These results were fitted smoothly with the high-temperature en- 
thalpy data of Dworkin ( 19 ) taken with a drop calorimeter. Their data span the tem- 
perature range 400.2 to 901.1 K for solid and 922.2 to 988.3 K for the liquid. They 
found the orthorhombic-to-hexagonal transition to occur at 774 K with an enthalpy of 
0.160 kcal/mol. The melting point was found to be 916 K with an enthalpy of fusion 
equal to 5.870 kcal/mol. These values are adopted. For the liquid segment, a con- 
stant heat capacity of 49 cal/(mol*K) was adopted on the basis of the enthalpy values 
reported by Dworkin (19) . 

Zr(S0 4 ) 2 (c) 

The standard enthalpy of formation has been measured by Melnikova ( 43 ) by hydro- 
chloric acid solution calorimetry. The enthalpy change of the reaction 

Zr(S0 4 ) 2 *0.03S0 3 (c) + 4KCl(c) + 0.03H 2 )(1) 

= ZrCl 4 (c) + 2K 2 S0 4 (c) + 0.03H 2 S0 4 (soln) 

was found to be AHr = 116.15 kJ(27.76 kcal) . The standard enthalpy of formation can 
be calculated using AHf £ 98 [ZrCl 4 ] = -234.35 kcal/mol (64), AHf 298 [K 2 S0 4 ] = -343.62 
kcal/mol U6 ) , AHf 298 [H 2 S0 4 -800H 2 0] = -213.208 kcal/mol (63), AHf 298 [KCl] = -104.385 
kcal/mol (65), and AHf 298 [H 2 0] = -68.315 kcal/mol ( 63J . 

Combining the above values yields AHf 2 98[ a-Zr (S0 4 ) 2 (c) ] = -536.16 kcal/mol, 
which is the adopted value. This value is compared with AHf 2 98[Zr(S0 4 ) 2 ] = -529.9 
kcal/mol reported by Wagman (64). 

Stern ( 61 ) estimated S 298 [Zr(S0 4 ) 2 ] = 31.8 cal/(mol*K). High-temperature en- 
thalpy values to 1,050 K have been measured by Smith (60) using an ice calorimeter. 



15 



[Formation: 



Ag 2 S0 4 (c) 
Silver sulfate 
2Ag(c) + S(c,l) + 2 2 (g) = Ag 2 S0 4 (c)] 



T, K 


cal/Cmol-K) 


kcal/mol 


Log Kf 




Cp* 


S° 


-(G° - Hl 98 )/T 


TjO TjO 

11 H 298 


AHf° 


AGf° 




298.15 


31.523 


48.020 


48.020 





-171.040 


-147.787 


108.329 


300 


31.606 


48.215 


48.022 


.058 


-171.040 


-147.642 


107.556 


368.3 


34.137 


54.979 


48.695 


2.314 


-170.967 


-142.322 


84.453 


368.3 


34.137 


54.979 


48.695 


2.314 


-171.063 


-142.322 


84.453 


388.36 


34.881 


56.810 


49.068 


3.006 


-171.024 


-140.757 


79.210 


388.36 


34.881 


56.810 


49.068 


3.006 


-171.437 


-140.757 


79.210 


400 


35.312 


57.846 


49.309 


3.415 


-171.427 


-139.838 


76.403 


432.02 


36.242 


60.601 


50.045 


4.561 


-171.404 


-137.311 


69.462 


500 


38.217 


66.046 


51.856 


7.095 


-171.392 


-131.940 


57.670 


600 


40.833 


73.247 


54.832 


11.049 


-171.075 


-124.072 


45.192 


699 


43.309 


79.645 


57.903 


15.198 


-170.547 


-116.356 


36.380 


699 


43.732 


85.229 


57.903 


19.099 


-166.646 


-116.356 


36.380 


700 


43.754 


85.316 


57.945 


19.160 


-166.622 


-116.286 


36.306 


717.82 


44.038 


86.419 


58.638 


19.942 


-166.494 


-115.006 


35.015 



Phase changes : 



AH 



0.096 kcal/mol. 



368.3 K, orthrhombic-monoclinic transformation of S; 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

698.6 K, first-order transition of Ag 2 S0 4 (c); AH° = 3.901 kcal/mol. 

717.824 K, boiling point of S to equilibrium of S n (n = 1 to 8). 

Sources: The enthalpy of formation and entropy at 298 K are from Parker (50) . The heat ca- 
pacity at 298 K is from Latimer (40). See text for high-temperature enthalpy values. 



[Formation: 



Ag 2 S0 4 (c,l) 
Silver sulfate 
2Ag(c) + 0.5S 2 (g) + 2 2 (g) = Ag 2 S0 4 (c,l) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H° 298 )/T 


H° - H 2 9 8 


AHf° 


AGf° 




298.15 


31.523 


48.020 


48.020 





-186.395 


-157.301 


115.303 


300 


31.606 


48.215 


48.022 


.058 


-186.392 


-157.119 


114.460 


400 


35.312 


57.846 


49.309 


3.415 


-186.078 


-147.403 


80.536 


500 


38.217 


66.046 


51.856 


7.095 


-185.520 


-137.794 


60.229 


600 


40.833 


73.247 


54.832 


11.049 


-184.770 


-128.312 


46.737 


699 


43.309 


79.645 


57.903 


15.198 


-183.876 


-119.067 


37.227 


699 


43.732 


85.229 


57.906 


19.099 


-179.975 


-119.067 


37.227 


700 


43.754 


85.316 


57.945 


19.160 


-179.947 


-118.982 


37.147 


800 


45.348 


91.263 


61.744 


23.615 


-178.859 


-110.349 


30.145 


900 


46.941 


96.696 


65.330 


28.229 


-177.683 


-101.858 


24.734 


926 


47.355 


98.039 


66.230 


29.455 


-177.362 


-99.672 


23.524 


926 


35.000 


102.963 


66.230 


34.015 


-172.802 


-99.671 


23.524 


1,000 


35.000 


105.653 


69.048 


36.605 


-172.807 


-93.826 


20.505 


1,025 


35.000 


106.518 


69.952 


37.480 


-172. R18 


-91.852 


19.584 



Phase changes 



698.6 K, first-order transition of Ag 2 S0 4 (c); AH° = 3.901 kcal/mol, 
926 K., melting point of Ag 2 S0 4 (c); AH° = 4.56 kcal/mol. 



Sources: The enthalpy of formation and entropy at 298 K. are from Parker (50) . The heat ca- 
pacity at 298 K. is from Latimer (40). See text for high-temperature enthalpy values. 



16 



[Formation: 



Al 2 (S0 4 ) 3 (c) 
Aluminum sulfate 
2Al(c) + 3S(c,l) + 6 2 (g) = Al 2 (S0 4 ) 3 (c)] 



T, K 


cal/(mol'K) 


kcal/mol 


Log Kf 




Cp 4 


S° 


-(G° - H| 98 )/T 


a h 298 


AHf° 


AGf° 













CO 


-9.614 


-814.440 


-814.440 


CO 


100 


12.860 


12.860 


100.510 


-8.765 


-818.453 


-793.673 


1,734.549 


200 


45.650 


35.790 


62.385 


-5.319 


-821.246 


-767.722 


838.917 


298.15 


62.000 


57.200 


57.200 





-822.620 


-741.116 


543.246 


300 


62.140 


57.584 


57.201 


.115 


-822.635 


-740.609 


539.527 


368.3 


71.093 


71.351 


58.558 


4.711 


-822.898 


-721.899 


428.370 


368.3 


71.093 


71.351 


58.558 


4.711 


-823.186 


-721.899 


428.370 


388.36 


73.722 


75.192 


59.320 


6.164 


-823.195 


-716.380 


403.138 


388.36 


73.722 


75.192 


59.320 


6.164 


-824.434 


-716.380 


403.138 


400 


75.248 


77.392 


59.814 


7.031 


-824.475 


-713.141 


389.637 


432.02 


78.156 


83.299 


61.339 


9.487 


-824.592 


-704.226 


356.249 


500 


84.331 


95.221 


65.145 


15.038 


-824.913 


-685.243 


299.516 


600 


90.414 


111.174 


71.512 


23.797 


-824.557 


-657.329 


239.429 


700 


94.191 


125.421 


78.215 


33.044 


-823.742 


-629.516 


196.541 


717.82 


94.570 


127.794 


79.417 


34.726 


-823.566 


-624.573 


190.157 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH°^ *■ 0.096 kcal/mol. 

388.36 K, melting point of S; AH° - 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH ■ kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation is from Wagman (63) corrected for the sulfate ion. The 
entropy at 298 K and low-temperature heat capacities are from Shomate (58); see discussion in 
text. The high-temperature enthalpy values are from Shomate (59). 



[Formation: 



Al 2 (S0 4 ) 3 (c) 
Aluminum sulfate 
2Al(c,l) + 1.5S 2 (g) + 6 2 (g) = Al 2 (S0 4 ) 3 (c)] 



T, K 




cal/(mo. 


L-K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H| 98 )/T( 


TjO TjO 

a H 298 


AHf° 


AGf° 













CO 


-3.614 


-860.394 


-860.394 


CO 


100 


21.870 


12.860 


100.510 


-8.765 


-865.015 


-834.143 


1,822.995 


200 


45.650 


35.790 


62.385 


-5.319 


-867.693 


-802.106 


876.490 


298.15 


62.000 


57.200 


57.200 





-868.685 


-769.657 


564.167 


300 


62.140 


57.584 


57.201 


.115 


-868.691 


-769.041 


560.239 


400 


75.248 


77.392 


59.814 


7.031 


-868.428 


-735.838 


402.038 


500 


84.331 


95.221 


65.145 


15.038 


-867.295 


-702.803 


307.191 


600 


90.414 


111.174 


71.512 


23.797 


-865.641 


-670.051 


244.063 


700 


94.191 


125.421 


78.215 


33.044 


-863.717 


-637.602 


199.066 


800 


96.318 


138.152 


84.927 


42.580 


-861.714 


-605.443 


165.397 


900 


97.440 


149.568 


91.486 


52.274 


-859.744 


-573.528 


139.270 


933.61 


97.693 


153.145 


93.642 


55.553 


-859.100 


-562.852 


131.757 


933.61 


97,693 


153.145 


93.642 


55.553 


-864.260 


-562.851 


131.757 


1,000 


98.194 


159.874 


97.818 


62.056 


-862.954 


-541.465 


'118.335 


1,100 


99.214 


169.276 


103.892 


71.922 


-860.982 


-509.408 


101.209 



Phase changes : 933.61 K, melting point of Al; AH° = 2.580 kcal/mol. 

Sources: The enthalpy of formation is from Wagman (63) corrected for the sulfte ion. The en- 
tropy at 298 K. and low-temperature heat capacities are from Shomate (58); see discussion in 
text. The high-temperature enthalpy values are from Shomate (59). 



17 



[Formation: 



Al 2 (S0 4 ) 3 -6H 2 0(c) 
Aluminum sulfate hexahydrate 
2Al(c) + 3S(c,l) + 9 2 (g) + 6H 2 (g) = Al 2 (S0 4 ) 3 -6H 2 0(c) ] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P u 


S° 


-CG° - H5 98 )/T 


ti "298 


AHf u 


AGf° 













00 


-18.137 


-1,251.744 


-1,251.744 


00 


100 


41.570 


29.710 


192.980 


-16.327 


-1,261.180 


-1,211.238 


2,647.125 


200 


84.140 


72.090 


121.925 


-9.967 


-1,267.011 


-1,158.799 


1,266.261 


298.15 


118.061 


112.188 


112.188 





-1,269.770 


-1,105.002 


809.978 


300 


118.652 


112.920 


112.190 


.219 


-1,269.798 


-1,103.979 


804.238 


350 


133.954 


132.376 


113.693 


6.539 


-1,270.155 


-1,076.306 


672.067 


368.3 


139.085 


139.334 


114.796 


9.037 


-1,270.127 


-1,066.171 


632.660 


368.3 


139.085 


139.334 


114.796 


9.037 


-1,270.415 


-1,066.172 


632.660 


388.36 


144.710 


146.871 


116.256 


11.890 


-1,270.293 


-1,055.046 


593.721 


388.36 


144.710 


146.871 


116.256 


11.890 


-1,271:. 532 


-1,055.047 


593.721 


400 


147.974 


151.193 


117.210 


13.593 


-1,271.474 


-1,048.560 


572.899 


432.02 


156.131 


162.909 


120.162 


18.468 


-1,271.208 


-1,030.725 


521.415 


450 


160.712 


169.369 


122.000 


21.316 


-1,271.182 


-1,020.715 


495.721 


500 


172.166 


186.906 


127.620 


29.643 


-1,270.256 


-992.929 


434.003 


550 


182.338 


203.803 


133.783 


38.511 


-1,268.808 


-965.259 


383.554 



Phase changes : 



AH 5 



368.3 K, orthorhombic-monoclinic transformation of S; 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



0.096 kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Wagman (63) . See text for entropy at 
298 K. Low-temperature heat capacities are from Shomate (58) . High-temperature heat capacities 
are estimated. 



[Formation: 



BaS0 4 (c) 
Barium sulfate 
Ba(c) + S(c,l) + 2 2 (g) = BaS0 4 (c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P u 


S° 


-(G u - H3 98 )/T 


TjO TJ° 

H H ?98 


AHf° 


AGf° 




298.15 


24.414 


31.600 


31.600 





-352.200 


-325.668 


238.718 


300 


24.537 


31.749 


31.602 


.044 


-352.204 


-325.503 


237.126 


368.3 


27.167 


37.063 


32.125 


1.818 


-352.261 


-319.417 


189.540 


368.3 


27.167 


37.063 


32.125 


1.818 


-352.357 


-319.418 


189.541 


388.36 


27.939 


38.524 


32.419 


2.371 


-352.363 


-317.623 


178.740 


388.36 


27.939 


38.524 


32.419 


2.371 


-352.776 


-317.623 


178.740 


400 


28.387 


39.356 


32.608 


2.699 


-352.795 


-316.569 


172.963 


432.02 


29.025 


41.567 


33.192 


3.618 


-352.868 


-313.667 


158.675 


500 


30.380 


45.929 


34.633 


5.648 


-353.153 


-307.474 


134.395 


582 


31.270 


50.618 


36.562 


8.180 


-353.524 


-299.955 


112.636 


582 


31.270 


50.618 


36.562 


8.180 


-353.524 


-299.955 


112.636 


600 


31.465 


51.573 


36.998 


8.745 


-353.538 


-298.298 


108.654 


700 


32.120 


56.476 


39.437 


11.927 


-353.627 


-298.084 


90*255 


717.82 


32.196 


57.284 


39.870 


12.500 


-353.648 


-287.440 


87.514 



Phase changes : 368.3 K, orthorhombic-monoclinic transformation of S; AH° =» 0.096 kcal/mol. 
388.36 K, melting point of S; AH° = 0.413 kcal/mol. 
432.02 K, second-order transformation of S; AH° = kcal/mol. 
582 K, a-6 transition point of Ba; AH° = kcal/mol. 
717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is from Parker (49) after correction for the sul- 
fate ion. The entropy at 298 K is from Parker (49) ; see discussion in text. The low-temper- 
ature heat capacity values are from Latimer (39) , while the relative high-temperature enthalpy 
values are from Lashchenko (36). 



18 



[Formation: 



BaS0 4 (c) 
Barium sulfate 
Ba(c,l) + 0.5S 2 (g) + 2 2 (g) = BaS0 4 (c)] 



T, K 




cal/(mo. 


L»K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H| 98 )/T 


TjO tjO 


AHf° 


AGf° 




298.15 


24. 414 


31.600 


31.600 





-367.555 


-335.182 


245.692 


300 


24.537 


31.749 


31.602 


.044 


-367.556 


-334.980 


244.030 


400 


28.387 


39.356 


32.608 


2.699 


-367.446 


-324.135 


177.097 


500 


30.380 


45.929 


34.633 


5.648 


-367.281 


-313.327 


136.953 


582 


31.270 


50.618 


36.562 


8.180 


-367.291 


-304.481 


114.336 


582 


31.270 


50.618 


36.562 


8.180 


-367.291 


-304.481 


114.336 


600 


31.465 


51.573 


36.998 


8.745 


-367.233 


-302.539 


110.198 


700 


32.120 


56.476 


39.437 


11.927 


-366.952 


-291.779 


91.096 


768 


32.409 


59.469 


41.080 


14.123 


-366.816 


-284.485 


80.955 


800 


32.545 


60.795 


41.842 


15.162 


-366.755 


-281.056 


76.780 


900 


32.836 


64.646 


44.166 


18.432 


-366.531 


-270.357 


65.651 


1,000 


33.043 


68.117 


46.391 


21.726 


-366.307 


-259.684 


56.753 


1,002 


33.046 


68.183 


46.434 


21.792 


-366.303 


-259.470 


56.593 


1,002 


33.046 


68.183 


46.434 


21.792 


-368.155 


-259.471 


56.593 


1,100 


33.194 


71.273 


48.511 


25.038 


-367.993 


-248.846 


49.441 


1,200 


33.308 


74.167 


60.530 


28.364 


-367.805 


-238.023 


43.349 


1,300 


33.394 


76.836 


52.452 


31.699 


-367.607 


-227.215 


38.198 



Phase changes : 582 K, a-$ transition point of Ba; AH° = kcal/mol. 
768 K, 6-y transition point of Ba; AH = kcal/mol. 
1,002 K, melting point of Ba; AH° = 1.852 kcal/mol. 

Sources: The enthalpy of formation at 298 K is from Parker ( 49 ) after correction for the sul- 
fate ion. The entropy at 298 K is from Parker (49); see discussion in text. The low-temper- 
ature heat capacity values are from Latimer (39) , while the relative high-temperature enthalpy 
values are from Lashchenko (36). 



[Formation: 



BeS0 4 (a,B,Y) 
Beryllium sulfate 

Be(c) + S(c,l) + 2 2 (g) = BeS0 4 (a,e,Y)] 



T, K 


cal/(mol*K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H| 98 )/T 


TjO TjO 

H tl 298 


AHf° 


AGf° 













OO 


-3.102 


-284.510 


-284.510 


OO 


100 


7.008 


4.453 


32.603 


-2.815 


-285.785 


-277.639 


606.772 


200 


14.502 


11.683 


20.323 


-1.728 


-286.621 


-268.885 


293.820 


298.15 


20.482 


18.635 


18.635 





-287.080 


-260.453 


190.915 


300 


20.581 


18.762 


18.635 


.038 


-287.085 


-260.289 


189.618 


368.3 


23.482 


23.309 


19.083 


1.556 


-287.206 


-254.172 


150.824 


368.3 


23.482 


23.309 


19.083 


1.556 


-287.302 


-254.172 


150.824 


388.36 


24.334 


24.577 


19.335 


2.036 


-287.320 


-252.367 


142.018 


388.36 


.24.334 


24.577 


19.335 


2.036 


-287.733 


-252.367 


142.018 


400 


24.828 


25.303 


19.498 


2.322 


-287.757 


-251.307 


137.306 


432.02 


25.783 


27.252 


20.001 


3.132 


-287.827 


-248.387 


125.652 


500 


27.810 


31.180 


21.258 


4.961 


-288.018 


-242.163 


105.848 


600 


30.310 


36.470 


23.360 


7.866 


-288.025 


-232.983 


84.863 


700 


32.980 


41.340 


25.584 


11.029 


-287.793 


-223.828 


69.881 


717.82 


33.483 


42.175 


25.986 


11.621 


-287.724 


-222.200 


67.651 



Phase changes: 



0.096 kcal/mol. 



368.3 K, orthorhombic-monoclinic transformation of S; AH 

388.36 K, melting point of S; AH = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° ■ kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is based on Navratil (44) after correction for 
the sulfate ion. Low-temperature heat capacity values, the entropy at 298 K, and the relative 
high-temperature enthalpy values are from JANAF (15). 



19 



[Formation: 



BeS0 4 (a,S,Y) 
Beryllium sulfate 
Be(c.l) + 0.5S 2 (g) + 2 2 (g) 



= BeS0 4 (a,S,Y)l 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S 6 


-(G° - H| 98 )/T 


TjO TjO 

H H 298 


AHf° 


AGf° 













00 


-3.102 


-299.828 


-299.828 


00 


100 


7.008 


4.453 


32.603 


-2.815 


-301.305 


-291.129 


636.254 


200 


14.502 


11.683 


20.323 


-1.728 


-302.103 


-280.346 


306.344 


298.15 


20.482 


18.635 


18.635 





-302.435 


-269.967 


197.889 


300 


20.581 


18.762 


18.635 


.038 


-302.437 


-269.766 


196.522 


400 


24.828 


25.303 


19.498 


2.322 


-302.408 


-258.872 


141.439 


500 


27.810 


31.180 


21.258 


4.961 


-302.145 


-248.017 


108.407 


600 


30.310 


36.470 


23.360 


7.866 


-301.719 


-237.224 


86.408 


700 


32.980 


41.340 


25.584 


11.029 


-301.118 


-226.524 


70.723 


800 


35.800 


45.927 


27.843 


14.467 


-300.309 


-215.920 


58.986 


863 


37.650 


48.709 


29.265 


16.780 


-299.682 


-209.295 


53.002 


863 


37.650 


49.017 


29.265 


17.046 


-299.416 


-209.295 


53.002 


900 


38.730 


50.620 


30.110 


18.459 


-299.003 


-205.439 


49.887 


908 


38.970 


50.964 


30.292 


18.770 


-298.909 


-204.608 


49.247 


908 


38.970 


56.110 


30.292 


23.443 


-294.236 


-204.608 


49.247 


1,000 


41.690 


60.004 


32.844 


27.160 


-293.037 


-195.582 


42.744 


1,100 


43.759 


64.080 


35.501 


31.437 


-291.547 


-185.909 


36.936 


1,200 


45.222 


67.953 


38.045 


35.890 


-289.924 


-176.380 


32.123 


1,300 


46.258 


71.616 


40.488 


40.466 


-288.221 


-166.982 


28.072 


1,400 


46.984 


75.072 


42.836 


45.130 


-286.471 


-157.720 


24.621 


1,500 


47.480 


78.331 


45.094 


49.855 


-284.697 


-148.596 


21.650 


1,527 


47.567 


79.179 


45.690 


51.138 


-284.218 


-146.144 


20.916 


1,527 


47.567 


79.179 


45.690 


51.138 


-284.829 


-146.144 


20.916 


1,560 


47.673 


80.198 


46.410 


52.710 


-284.243 


-143.162 


20.056 


1,560 


47.673 


80.198 


46.410 


52.710 


-287.162 


-143.164 


20.056 


1,600 


47.802 


81.407 


47.269 


54.620 


-286.424 


-139.478 


19.052 


1,700 


47.970 


84.310 


49.363 


59.410 


-284.571 


-130.360 


16.759 


1,800 


48.000 


87.053 


51.381 


64.209 


-282.724 


-121.345 


14.733 


1,900 


48.000 


89.649 


53.328 


69.009 


-280.892 


-112.414 


12.930 


2,000 


48.000 


92.111 


55.207 


73.809 


-279.073 


-103.597 


11.320 



Phase changes : 



863 K, a-g transition point of BeS0 4 ; AH° = 0.266 kcal/mol. 
908 K, 8-y transition point of BeS0 4 ; AH° = 4.673 kcal/mol. 
1,527 K, a-6 transition point of Be; AH = 0.611 kcal/mol. 
1,560 K, melting point of Be; AH° = 2.919 kcal/mol. 



Sources: The enthalpy of formation at 298 K is based on Navratil (44) after correction for 
the sulfate ion. Low-temperature heat capacity values, the entropy at 298 K, and the relative 
high-temperature enthalpy values are from JANAF (15). 



20 



[Formation: 



BeS0 4 'H 2 0(c) 
Beryllium sulfate monohydrate 
Be(c) + S(c,l) + 2.5 2 (g) = BeS0 4 -H 2 0(c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H5 98 )/T 


TjO Tjfl 

H u 298 


AHf° 


AGf° 




298.15 


28.560 


28.910 


28.910 





-361.150 


-320.977 


235.280 


300 


28.726 


29.087 


28.910 


.503 


-361.159 


-320.728 


233.647 


350 


33.227 


33.853 


29.276 


1.602 


-361.326 


-313.974 


196.052 


368.3 


34.874 


35.588 


29.547 


2.225 


-361.342 


-311.498 


184.841 


368.3 


34.874 


35.588 


29.547 


2.225 


-361.438 


-311.498 


184.841 


388.36 


36.679 


37.485 


29.907 


2.943 


-361.429 


308.777 


173.762 


388.36 


36.679 


37.485 


29.907 


2.943 


-361.842 


-308.777 


173.762 


400 


37.727 


38.584 


20.144 


3.376 


-361.841 


-307.187 


167.837 


432.02 


40.609 


41.598 


30.883 


4.629 


-361.808 


-302.814 


153.185 


450 


42.227 


43.287 


31.345 


5.374 


-361.829 


-300.360 


145.873 


500 


46.727 


47.969 


32.773 


7.598 


-361.584 


-293.541 


128.305 


550 


51.227 


52.634 


34.367 


10.047 


-361.126 


-286.752 


113.943 



Phase changes: 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH = kcal/mol. 



Sources: The enthalpy of formation at 298 K is based on Broers 
The entropy and heat capacity value at 298 K are from Broers (_5) . 
ities are estimated. 



( _5) ; see discussion in text. 
High-temperature heat capac- 



[ Formation: 



BeS0 4 «2H 2 0(c) 
Beryllium sulfate dihydrate 
Be(c,l) + S(c,l) + 3 2 (g) + 2H 2 (g) 



BeS0 4 «2H 2 0) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H2 98 )/T 


U° - u°~~ 
u u 298 


AHf° 


AGf° 













00 


-5.865 


-428.770 


-428.770 


00 


100 


14.330 


12.890 


64.290 


-5.140 


-431.735 


-415.484 


908.027 


200 


26.280 


26.250 


42.040 


-3.104 


-433.606 


-398.188 


435.114 


298.15 


36.630 


39.010 


39.010 


0.000 


-434.780 


-381.009 


279.283 


300 


36.808 


39.237 


39.010 


0.068 


-434.794 


-380.676 


277.318 


350 


41.383 


45.261 


39.475 


2.025 


-435.075 


-371.631 


232.054 


368.3 


42.892 


47.409 


39.817 


2.796 


-435.135 


-368.312 


218.554 


368.3 


42.892 


47.409 


39.817 


2.796 


-435.231 


-368.312 


218.554 


388.36 


44.546 


49.731 


40.269 


3.675 


-435.272 


-364.665 


205.213 


388.36 


44.546 


49.731 


40.269 


3.675 


-435.686 


-364.665 


205.213 


400 


45.506 


51.061 


40.563 


4.199 


-435.717 


-362.536 


198.078 


432.02 


47.856 


54.659 


41.475 


5.696 


-435.779 


-356.676 


180.432 


450 


49.175 


56.637 


42.041 


6.568 


-435.864 


-353.384 


171.625 


500 


52.392 


61.988 


43.770 


9.109 


-435.836 


-344.219 


150.456 


550 


55.155 


67.115 


45.662 


11.799 


-435.674 


-335.061 


133.139 



Phase changes : 368.3 K, orthorhombic-monoclinic transformation of S; AH = 0.096 kcal/mol. 
388.36 K, melting point of S; AH = 0.413 kcal/mol. 
432.02 K, second-order transformation of S; AH° = kcal/mol. 
717.824 K, boiling point of S to equilibrium mixture of S n (n - 1 to 8). 

Sources: The enthalpy of formation at 298 K. is from Navratil (44) . The entropy at 298 K and 
low-temperature heat capacity values are from Gardner (23). High-temperature heat capacities 
are estimated. 



21 



[Formation: 



BeS0 4 «4H 2 0(c) 
Beryllium sulfate tetrahydrate 
Be(c,l) + S(c,l) + 4 2 (g) + 4H 2 (g) = BeS0 4 -4H 2 0)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S* 


-(G° - H 298 )/T 


TjO TjO 

H hl 298 


AHf° 


AGf° 













00 


-8.306 


-568.688 


-568.688 


OO 


100 


20.880 


18.850 


91.140 


-7.229 


-573.429 


-548.825 


1,199.440 


200 


36.720 


38.180 


59.840 


-4.332 


-576.423 


-522.688 


571.159 


298.15 


51.770 


55.680 


55.680 


0.000 


-578.380 


-496.359 


363.836 


300 


52.049 


56.001 


55.681 


0.096 


-578.405 


-495.851 


361.223 


350 


59.503 


64.586 


56.343 


2.885 


-578.899 


-482.049 


301.001 


368.3 


62.184 


67.687 


56.830 


3.998 


-579.001 


-476.982 


283.038 


368.3 


62.184 


67.687 


56.830 


3.998 


-579.097 


-476.982 


283.038 


388.36 


65.124 


71.063 


57.477 


5.276 


-579.162 


-471.417 


265.287 


388.36 


65.124 


71.063 


57.477 


5.276 


-579.575 


-471.417 


265.287 


400 


66.829 


73.011 


57.901 


6.044 


-579.609 


-468.175 


255.795 


432.02 


71.437 


78.333 


59.218 


8.258 


-579.632 


-459.253 


232.323 


450 


74.025 


81.299 


60.041 


9.566 


-579.665 


-454.245 


220.609 


500 


81.091 


89.465 


62.575 


13.445 


-579.366 


-440.321 


192.462 


550 


88.028 


97.520 


65.387 


17.673 


-578.740 


-426.440 


169.450 



Phase changes 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Navratil (44). Th entropy at 298 K and 
low-temperature heat capacity values are from Gardner (23) . High-temperature heat capacities 
are estimated. 



CaS0 4 (i,c) 

Calcium sulfate (insoluble anhydrite) 

[Formation: Ca(c) + S(c,l) + 2 2 (g) = CaS0 4 (i,c) 



T, K 




cal/(mo. 


L-K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - Hl 98 )/T 


H - H 298 


AHf° 


AGf° 













oa 


-4.105 


-340.370 


-340.370 


CO 


100 


11.007 


6.707 


43.307 


-3.660 


-341.711 


-333.422 


728.685 


200 


19.067 


17.073 


27.663 


-2.118 


-342.496 


-324.790 


354.909 


298.15 


23.878 


25.620 


25.620 





-342.840 


-316.009 


231.638 


300 


23.965 


25.771 


25.621 


.045 


-342.842 


-315.841 


230.087 


368.2 


25.873 


30.956 


26.140 


1.774 


-342.881 


-309.689 


183.768 


368.3 


25.873 


30.956 


26.140 


1.774 


-342.977 


-309.689 


183.768 


388.36 


26.434 


32.344 


26.425 


2.298 


-342.983 


-307.876 


173.255 


388.36 


26.434 


32.344 


26.425 


2.298 


-343.396 


-307.876 


173.255 


400 


26.759 


33.129 


26.609 


2.608 


-343.415 


-306.811 


167.632 


432.02 


27.483 


35.218 


27.171 


3.476 


-343.475 


-303.879 


153.724 


500 


20.019 


39.343 


28.549 


5.397 


-343.668 


-297.630 


130.092 


600 


31.279 


44.833 


30.813 


8.412 


-343.704 


-288.412 


105.053 


700 


33.538 


49.825 


33.178 


11.653 


-343.551 


-279.212 


87.173 


717.82 


33.941 


50.673 


33.602 


12.254 


-343.505 


-277.572 


84.509 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is from Parker (49^) corrected for the heat of 
formation of the sulfate ion. See text for discussion of entropy values at 298 K. Low-temper- 
ature heat capacities from Kelley (31) . The high-temperature enthalpies are from Lashchenko 
(37). 



22 



CaS0 4 (i,c) 

Calcium sulfate (insoluble anhydrite) 

formation: Ca(c,l) + 0.5S 2 (g) + 2 2 (g) = CaS0 4 (i,c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H| 98 )/T 


a u 298 


AHf° 


AGf° 













OS 


-4.105 


-355.688 


-355.688 


OO 


100 


11.007 


6.707 


43.307 


-3.660 


-357.232 


-346.912 


758.166 


200 


19.067 


17.073 


27.663 


-2.118 


-357.979 


-336.251 


367.434 


298.15 


23.878 


25.620 


25.620 





-358.195 


-325.523 


238.612 


300 


23.965 


25.771 


25.621 


.045 


-358.194 


-325.319 


236.991 


400 


26.759 


33.129 


26.609 


2.608 


-358.066 


-314.377 


171.765 


500 


29.019 


39.343 


28.549 


5.397 


-357.796 


-303.483 


132.651 


600 


31.279 


44.833 


30.813 


8.412 


-357.398 


-292.653 


106.597 


700 


33.538 


49.825 


33.178 


11.653 


-356.876 


-281.907 


88.014 


720 


33.990 


50.776 


33.654 


12.328 


-356.758 


-279.765 


84.919 


720 


33.99G 


50.776 


33.654 


12.328 


-356.978 


-279.765 


84.919 


800 


35.798 


54.451 


35.551 


15.120 


-356.406 


-271.212 


74.091 


900 


38.058 


58.797 


37.895 


18.812 


-355.592 


-260.596 


63.280 


1,000 


40.318 


62.924 


40.193 


22.731 


-354.719 


-250.105 


54.660 


1,100 


42.577 


66.873 


42.440 


26.876 


-353.727 


-239.687 


47.621 


1,112 


42.848 


67.336 


42.706 


27.389 


-353.600 


-238.452 


46.864 


1,112 


42.848 


67.336 


42.706 


27.389 


-355.641 


-238.452 


46.864 


1,200 


44.837 


70.674 


44.635 


31.247 


-354.288 


-229.225 


41.747 


1,300 


47.097 


74.352 


46.780 


35.843 


-352.559 


-218.874 


36.796 


1,400 


49.356 


77.925 


48.878 


40.666 


-350.623 


-208.660 


32.573 



Phase changes : 



720 K, a-e transition point of Ca; AH° = 0.220 kcal/mol. 
1,112 K, melting point of Ca; AH° = 2.040 kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Parker ( 49 ) corrected for the heat of 
formation of the sulfate ion. See text for discussion of entropy values at 298 K. Low-temper- 
ature heat capacities are from Kelley (31) . The high-temperature enthalpies are from Lashchenko 
(37). 

CaS0 4 (8,c) 

Calcium sulfate (g-soluble anhydrite) 

[Formation: Ca(c) + S(c,l) + 2 2 (g) = CaS0 4 (B,c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H| 98 )/T 


TjO TjO 

H u 298 


AHf° 


AGf° 













00 


-4.146 


-337.231 


-337.231 


OO 


100 


11.576 


6.579 


43.479 


-3.690 


-338.561 


-330.260 


721.772 


200 


19.149 


17.138 


27.758 


-2.124 


-339.322 


-321.629 


351.455 


298.15 


23.690 


25.720 


25.720 





-339.660 


-312.859 


229.329 


300 


23.754 


25.871 


25.721 


.045 


-339.662 


-312.691 


227.793 


368.3 


25.806 


31.059 


26.240 


1.775 


-339.700 


-306.546 


181.903 


368.3 


25.806 


31.059 


26.240 


1.775 


-339.796 


-306.546 


181.903 


388.36 


26.409 


32.444 


26.525 


2.299 


-339.803 


-304.734 


171.487 


388.36" 


26.409 


32.444 


26.525 


2.299 


-340.216 


-304.735 


171.487 


400 


26.759 


33.229 


26.709 


2.608 


-340.235 


-303.671 


165.916 


432.02 


27.483 


35.318 


27.271 


3.476 


-340.296 


-300.742 


152.137 


500 


20.019 


39.443 


28.649 


5.397 


-340.488 


-294.500 


128.724 


600 


31.279 


44.933 


30.913 


8.412 


-340.524 


-285.292 


103.916 


700 


33.538 


49.925 


33.278 


11.653 


-340.371 


-276.102 


86.202 


717.82 


33.941 


50.773 


33.702 


12.254 


-340.325 


-274.464 


83.563 


Phase ch 


ange : 368 


.3 K, ortl 


"lorhombic-monoclii 


lie transforma 


tion of S; AH' 


' = 0.096 kca 


1/mol. 



388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mo 

717.824 K, boiling point of S to equilibrium mixture of S n 

Sources: The enthalpy of formation at 298 K is from Parker (49) correc 
formation of the sulfate ion. See text for discussion of entropy values at 
ature heat capacities are from Kelley (31) . The high-temperature enthalpies 
(37). 



1. 

(n = 1 to 8). 

ted for the heat of 
298 K. Low-temper- 
are from Lashchenko 



23 



CaS0 4 (p\c) 

Calcium sulfate (S-soluble anhydrite) 

[Formation: Ca(c,l) + 0.5S 2 (g) + 2 2 (g) = CaS0 4 (p\c); 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H| 98 )/T 


H ti 298 


AHf° 


AGf° 













00 


-4.146 


-352.549 


-352.549 


OO 


100 


11.576 


6.579 


43.479 


-3.690 


-354.082 


-343.749 


751.254 


200 


19.149 


17.138 


27.758 


-2.124 


-354.805 


-333.090 


363.979 


298.15 


23.690 


25.720 


25.720 





-355.015 


-322.373 


236.302 


300 


23.754 


25.871 


25.721 


.045 


-355.014 


-322.169 


234.697 


400 


26.759 


33.229 


26.709 


2.608 


-354.886 


-311.237 


170.050 


500 


29.019 


39.443 


28.649 


5.397 


-354.616 


-300.353 


131.283 


600 


31.279 


44.933 


30.913 


8.412 


-354.219 


-289.533 


105.461 


700 


33.538 


49.925 


33.278 


11.653 


-353.696 


-278.797 


87.043 


720 


33.990 


50.876 


33.754 


12.328 


-353.578 


-276.657 


83.976 


720 


33.990 


50.876 


33.754 


12.328 


-353.798 


-276.657 


83.976 


800 


35.798 


54.551 


35.651 


15.120 


-353.227 


-268.112 


73.244 


900 


38.058 


58.897 


37.995 


18.812 


-352.413 


-257.506 


62.530 


1,000 


40.318 


63.024 


40.293 


22.731 


-351.539 


-247.025 


53.986 


1,100 


42.577 


66.973 


42.540 


26.876 


-350.547 


-236.617 


47.011 


1,112 


42.848 


67.436 


42.806 


27.389 


-350.421 


-235.384 


46.261 


1,112 


42.848 


67.436 


42.806 


27.389 


-352.461 


-235.384 


46.261 


1,200 


44.837 


70.774 


44.735 


31.247 


-351.108 


-226.165 


41.190 


1,300 


47.097 


74.452 


46.880 


35.843 


-349.379 


-215.824 


36.283 


1,400 


49.356 


78.025 


48.978 


40.666 


-347.443 


-205.620 


32.098 



Phase changes : 



720 K, a-3 transition point of Ca; AH° = 0.220 kcal/mol. 
1,112 K, melting point of Ca; AH° = 2.040 kcal/mol. 



Source- The enthalpy of formation at 298 K is from Parker ( 49 ) corrected for the heat of 
formation )f the sulfate ion. See text for discussion of entropy values at 298 K. Low-temper- 
ature heac capacities are from Kelley ( 31 ) . The high-temperature enthalpies are from Lashchenko 
(37). 

CaS0 4 (a,c) 
Calcium sulfate (a-soluble anhydrite) 







[Formation: Ca(c) + S(c 


,1) + 2 2 (g) 


= CaS0 4 (a,c)] 






T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S* 


-(G° - H| 98 )/T 


nO TlO 

H "298 


AHf° 


AGf° 













OO 


-4.156 


-338.301 


-338.301 


OO 


100 


11.350 


6.920 


43.860 


-3.694 


-339.625 


-331.358 


724.172 


200 


19.149 


17.450 


28.095 


-2.129 


-340.387 


-322.756 


352.687 


298.15 


23.940 


26.050 


26.050 





-340.720 


-314.017 


230.178 


300 


24.010 


26.201 


26.051 


.045 


-340.722 


-313.850 


228.637 


368.3 


25.888 


31.386 


26.570 


1.774 


-340.761 


-307.728 


182.604 


368.3 


25.888 


31.386 


26.570 


1.774 


-340.857 


-307.728 


182.604 


388.36 


26.439 


32.773 


26.855 


2.298 


-340.863 


-305.923 


172.156 


388.36 


26.439 


32.773 


26.855 


2.298 


-341.276 


-305.923 


172.156 


400 


26.759 


33.559 


27.039 


2.608 


-341.295 


-304.863 


166.567 


432.02 


27.483 


35.647 


27.601 


3.476 


-341.355 


-301.945 


152.746 


500 


29.019 


39.773 


28.979 


5.397 


-341.548 


-295.725 


129.260 


600 


31.279 


45.263 


31.243 


8.412 


-341.584 


-286.550 


104.375 


700 


33.538 


50.255 


33.608 


11.653 


-341.431 


-277.393 


86.605 


717.82 


33.941 


51.103 


34.032 


12.254 


-341.385 


-275.761 


83.958 



Phase changes : 368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 
388.36 K, melting point of S; AH° = 0.413 kcal/mol. 
432.02 K, second-order transformation of S; AH° = kcal/mol. 
717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is from Parker (49) corrected for the heat of 
formation of the sulfate ion. See text for discussion of entropy values at 298 K. Low-temper- 
ature heat capacities are from Kelley (31). The high-temperature enthalpies are from Lashchenko 
(37). 



24 



CaS0 4 (a,c) 
Calcium sulfate (a-soluble anhydrite) 
[Formation: Ca(c,l) + 0.5S 2 (g) + 2 2 (g) = CaS0 4 (a,c)] 



T, K 




cal/(mo] 


■•K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - Hl 98 )/T 


TjO TjO 

h "298 


AHf° 


AGf° 




. 








OO 


-4.156 


-353.619 


-353.619 


OO 


100 


11.350 


6.920 


43.860 


-3.694 


-355.146 


-344.848 


753.654 


200 


19.149 


17.450 


28.095 


-2.129 


-355.870 


-334.218 


365.211 


298.15 


23.940 


26.050 


26.050 





-356.075 


-323.531 


237.152 


300 


24.010 


26.201 


26.051 


.045 


-356.074 


-323.328 


235.541 


400 


26.759 


33.559 


27.039 


2.608 


-355.946 


-312.429 


170.701 


500 


29.019 


39.773 


28.979 


5.397 


-355.676 


-301.578 


131.818 


600 


31.279 


45.263 


31.243 


8.412 


-355.279 


-290.791 


105.919 


700 


33.538 


50.255 


33.608 


11.653 


-354.756 


-280.088 


87.446 


720 


33.990 


51.206 


34.084 


12.328 


-354.638 


-277.954 


84.370 


720 


33.990 


51.206 


34.084 


12.328 


-354.858 


-277.954 


84.370 


800 


35.798 


54.881 


35.981 


15.120 


-354.286 


-269.436 


73.606 


900 


38.058 


59.227 


38.325 


18.812 


-353.473 


-258.863 


62.860 


1,000 


40.318 


63.354 


40.623 


22.731 


-352.599 


-248.415 


54.290 


1,100 


42.577 


67.303 


42.870 


26.876 


-351.607 


-238.040 


47.294 


1,112 


42.848 


67.766 


43.136 


27.389 


-351.480 


-236.810 


46.542 


1,112 


42.848 


67.766 


43.136 


27.389 


-353.521 


-236.810 


46.542 


1,200 


44.837 


71.104 


45.065 


31.247 


-352.168 


-227.621 


41.455 


1,300 


47.097 


74.782 


47.210 


35.843 


-350.439 


-217.313 


36.533 


1,400 


49.356 


78.355 


49.308 


40.666 


-348.503 


-207.142 


32.336 



Phase changes 



720 K, ci-B transition point of Ca; AH° = 0.220 kcal/mol. 
1,112 K, melting point of Ca; AH° = 2.040 kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Parker (49) corrected for the heat of 
formation of the sulfate ion. See text for discussion of entropy values at 298 K. Low-temper- 
ature heat capacities are from Kelley ( 31 ) . The high-temperature enthalpies are from Lashchenko 
(37). 

CaS0 4 '2H 2 0(c) 
Calcium sulfate dihydrite 





[Formation: Ca(c) + S(c,l) + 


2H 2 (g) + 3 2 (g) = CaS0 4 -2H 2 0(c)] 




T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P a 


S° 


-(G° - Hl 98 )/T 


TjO TjO 

H "298 


AHf° 


AGf° 













00 


-7.419 


-478.221 


-487.221 


OO 


100 


19.150 


12.410 


78.530 


-6.612 


-481.328 


-464.661 


1,015.502 


200 


34.310 


30.630 


50.120 


-3.898 


-482.925 


-447.281 


488.760 


298.15 


44.102 


46.400 


46.400 





-483.500 


-429.645 


314.934 


300 


44.236 


46.673 


46.400 


.082 


-483.504 


-429.309 


312.748 


350 


47.157 


53.729 


46.952 


2.372 


-483.547 


-420.273 


262.427 


368.3 


47.742 


56.147 


47.349 


3.240 


-483.543 


-416.964 


247.424 


368.3 


47.742 


56.147 


47.349 


3.240 


-483.639 


-416.964 


247.424 


388.36 


48.384 


58.711 


47.871 


4.210 


-483.623 


-413.333 


232.600 


388.36 


48.384 


58.711 


47.871 


4.210 


-484.036 


-413.333 


232.600 


400 


48.756 


60.145 


48.208 


4.775 


-484.045 


-411.214 


224.674 


432.02 


48.933 


63.919 


49.231 


6.345 


-484.082 


-405.382 


205.071 


450 


49.033 


65.916 


49.858 


7.226 


-484.182 


-402.106 


195.287 


500 


47.988 


71.040 


51.726 


9.657 


-484.334 


-392.978 


171.768 


550 


45.621 


75.513 


53.691 


12.002 


-484.584 


-383.829 


152.518 



Phase changes : 



AH 



368.3 K, orthorhombic-monoclinic transformation of S; 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



0.096 kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Parker ( 49 ) corrected for the heat of 
formation of the sulfate ion. The entropy at 298 K is from Parker (49) . Low-temperature heat 
capacity values are from Latimer (39), while the high-temperature values are estimated. 



25 



CaS0 4 'l/2H 2 0(a,c) 
Calcium sulfate hemihydrite (a-soluble hemlhydrate) 
[Formation: Ca(c) + S(c,l) + 0.5H 2 (g) + 2.25 2 (g) = CaS0 4 «l/2H 2 0(a,c)] 



T, K 


cal/(mol-K) 


kcal/mol 


Log Kf 




Cp a 


S° 


-(6° - H5 98 )/T 


TjO TjO 

H H 298 


AHf° 


AGf° 




298.15 


28.543 


31.200 


31.200 





-376.930 


-343.458 


251.758 


300 


28.632 


31.377 


31.200 


.053 


-376.934 


-343.249 


250.053 


350 


30.745 


35.957 


31.557 


1.540 


-376.997 


-337.629 


210.822 


368.3 


31.295 


37.538 


31.815 


2.108 


-377.004 


-335.570 


199.126 


368.3 


31.295 


37.538 


31.815 


2.108 


-377.100 


-335.570 


199.126 


388.36 


31.899 


39.220 


32.155 


2.744 


-377.101 


-333.308 


187.567 


388.36 


31.899 


39.220 


32.155 


2.744 


-377.514 


-333.308 


187.567 


400 


32.249 


40.167 


32.375 


3.117 


-377.530 


-331.983 


181.385 


432.02 


32.822 


42.678 


33.044 


4.162 


-377.584 


-328.335 


166.095 


450 


33.144 


44.023 


33.456 


4.755 


-377.684 


-326.284 


158.463 


500 


33.429 


47.536 


34.694 


6.421 


-377.801 


-320.567 


140.118 


550 


33.105 


50.711 


36.007 


8.087 


-377.924 


-314.835 


125.102 



Ptfese changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° =» kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Parker (49) corrected for the heat of 
formation of the sulfate ion. The entropy at 298 K is from Parker (49) . The heat capacity at 
298 K is from Kelley (31). High-temperature heat capacities are estimated. 



CaS0 4 .l/2H 2 0(8,c) 

Calcium sulfate hemihydrite ( 8-soluble hemihydrate) 

[Formation: Ca(c) + S(c,l) + 0.5H 2 (g) + 2.25 2 (g) = CaS0 4 «l/2H 2 0(S,c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp" 


S° 


-(G° - H5 98 )/T 


TjO TJO 

tl H 298 


AHf° 


AGf° 




298.15 


29.690 


32.100 


32.100 





-376.430 


-343.226 


251.588 


300 


29.802 


32.284 


32.101 


.055 


-376.432 


-343.019 


249.886 


350 


32.995 


37.119 


32.476 


1.625 


-376.412 


-337.451 


210.711 


368.3 


34.137 


38.830 


32.750 


2.239 


-376.373 


-335.415 


199.033 


368.3 


34.137 


38.830 


32.750 


2.239 


-376.469 


-335.415 


199.033 


388.36 


35.388 


40.673 


33.111 


2.937 


-376.408 


-333.179 


187.494 


388.36 


35.388 


40.673 


33.111 


2.937 


-376.821 


-333.179 


187.494 


400 


36.114 


41.729 


33.347 


3.353 


-376.794 


-331.872 


181.324 


432.02 


38.064 


44.585 


34.074 


4.541 


-376.705 


-328.280 


166.068 


450 


39.159 


46.159 


34.526 


5.235 


-376.704 


-326.265 


158.454 


500 


42.129 


50.439 


35.903 


7.268 


-376.453 


-320.672 


140.164 


550 


45.025 


54.591 


37.415 


9.447 


-376.064 


-315.109 


125.211 



Phase changes 



AH 



368.3 K, orthorhombic-monoclinic transformation of S; 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



0.096 kcal/mol, 



Sources: The enthalpy of formation at 298 K is from Parker (49) corrected for the heat of 
formation of the sulfate ion. The entropy at 298 K is from Parker (49) . Low-temperature heat 
capacity values are from Latimer (39), while the high-temperature valkues are estimated. 



26 



[Formation: 



CdS0 4 (c) 
Cadmium sulfate 
Cd(c,l) + S(c,l) + 2 2 (g) = CdS0 4 (c) 



T, K. 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S" 


-(G° - H| 98 )/T 


H "298 


AHf° 


AGf° 




298.15 


23.806 


29.408 


29.408 





-223.100 


-196.671 


144.162 


300 


23.875 


29.555 


29.408 


.044 


-223.103 


-196.506 


143.152 


368.3 


25.922 


34.652 


29.917 


1.744 


-223.183 


-190.442 


113.007 


368.3 


25.922 


34.652 


29.917 


1.744 


-223.279 


-190.442 


113.007 


388.36 


26.523 


36.044 


30.198 


2.270 


-223.288 


-188.653 


106.163 


388.36 


26.523 


36.044 


30.198 


2.270 


-223.701 


-188.653 


106.163 


400 


26.872 


36.832 


30.380 


2.581 


-223.721 


-187.602 


102.500 


432.02 


27.718 


38.934 


30.937 


3.455 


-223.783 


-184.709 


93.439 


500 


29.513 


43.117 


32.311 


5.403 


-223.962 


-178.541 


78.039 


594.26 


31.806 


48.409 


34.452 


8.294 


-223.953 


-169.976 


62.511 


594.26 


31.806 


48.409 


34.452 


8.294 


-225.433 


-169.976 


62.511 


600 


31.946 


48.715 


34.587 


8.477 


-225.428 


-169.435 


61.716 


700 


34.289 


53.816 


36.975 


11.789 


-225.182 


-160.123 


49.992 


717.82 


34.701 


54.683 


37.403 


12.404 


-225.112 


-158.467 


48.247 



Phase changes 



368.3 K, orthorhombic-monoclinic transformation of S; AH° «* 0.O96 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

594.26 K, melting point of Cd; AH° = 1.480 kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is based on Adami (1); see text. The entropy and 
heat capacity at 298 K are from Papadopoulos (47). High-temperature enthalpies were estimated. 



[Formation: 



CdS0 4 (c) 
Cadmium sulfate 
Cd(c,l) + 0.5S 2 (g) + 2 2 (g) = CdS0 4 (c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P 6 


S* 


-(G° - H| 98 )/T 


tjb tjO 

11 H 298 


AHf° 


AGf° 




298.15 


23.806 


29.408 


29.408 





-238.455 


-206.185 


151.136 


300 


23.875 


29.555 


29.408 


.044 


-238.455 


-205.983 


150.056 


400 


26.872 


36.832 


30.380 


2.581 


-238.372 


-195.168 


106.633 


500 


29.513 


43.117 


32.311 


5.403 


-238.090 


-184.394 


80.598 


594.26 


31.806 


48.409 


34.452 


8.294 


-237.670 


-174.307 


64.104 


594.26 


31.806 


48.409 


34.452 


8.294 


-239.150 


-174.307 


64.104 


600 


31.946 


48.715 


34.587 


8.477 


-239.122 


-173.676 


63.261 


700 


34.289 


53.816 


36.975 


11.789 


-238.507 


-162.818 


50.833 


800 


36.600 


58.546 


39.380 


15.333 


-237.705 


-152.059 


41.540 



Phase changes : 594.26 K, melting point of Cd; AH° = 1.480 kcal/mol. 

Sources: The enthalpy of formation at 298 K is based on Adami ( 1_) ; see text. The entropy and 
heat capacity at 298 K are from Papadopoulos (47). High-temperature enthalpies were estimated. 



27 



[Formation: 



CdS0 4 'H 2 0(c) 
Cadmium sulfate monohydrate 
Cd(c) + S(c,l) + H 2 (g) + 2.5 2 (g) = CdS0 4 -H 2 0(c)] 



T, K 


cal/(mo] 


•K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - Hl 98 )/T 


TjO TTO 

" "298 


AHf° 


AGf° 




298.15 


32.167 


36.814 


36.814 





-296.340 


-255.509 


187.291 


300 


32.284 


37.013 


36.813 


.060 


-296.346 


-255.254 


185.950 


350 - 


35.284 


42.220 


37.220 


1.750 


-296.477 


-248.397 


155.104 


368.3 


36.259 


44.043 


37.514 


2.405 


-296.497 


-245.882 


145.905 


368.3 


36.259 


44.043 


37.514 


2.405 


-296.593 


-245.882 


145.905 


388.36 


37.329 


45.997 


37.902 


3.144 


-296.600 


-243.119 


136.814 


388.36 


37.329 


45.997 


37.902 


3.144 


-297.013 


-243.119 


136.814 


400 


37.949 


47.109 


38.154 


3.582 


-297.029 


-241.504 


131.950 


432.02 


39.440 


50.091 


38.928 


4.822 


-297.063 


-237.058 


119.921 


450 


40.278 


51.716 


39.407 


5.539 


-297.141 


-234.559 


113.916 


500 


42.273 


56.066 


40.856 


7.605 


-297.133 


-227.603 


99.484 


550 


43.933 


60.176 


42.429 


9.761 


-297.039 


-220.655 


87.679 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Wagman ( 63 ) after correction for the heat 
of formation of the sulfate ion. The entropy and heat capacity at 298 K are from Papadopoulos 
(47). High-temperature enthalpies were estimated. 



[Formation: 



CdS0 4 .8/3H 2 0(c) 
Cadmium sulfate 8/3 hydrate 
Cd(c) + S(c,l) + 2.667H 2 (g) + 3.3333 2 (g) = CdS0 4 «8/3H 2 0(c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P 4 


S a 


-(6° - Hi 98 )/T 


TjO IjO 

H "298 


AHf° 


AGf° 




298.15 


50.985 


54.883 


54.883 


, 


-413.410 


-350.281 


256.760 


300 


51.209 


55.199 


54.882 


.095 


-413.414 


-349.888 


254.890 


350 


57.141 


63.542 


55.531 


2.804 


-413.396 


-339.300 


211.866 


368.3 


59.214 


66.507 


56.003 


3.869 


-413.327 


-335.428 


199.041 


368.3 


59.214 


66.507 


56.003 


3.869 


-413.423 


-335.428 


199.041 


388.36 


61.486 


69.710 


56.627 


5.081 


-413.309 


-331.181 


186.370 


388.36 


61.486 


69.710 


56.627 


5.081 


-413.722 


-331.181 


186.370 


400 


62.805 


71.545 


57.035 


5.804 


-413.658 


-328.709 


179.596 


432.02 


66.261 


76.515 


58.295 


7.871 


-413.431 


-321.917 


162.849 


450 


68.201 


79.256 


59.078 


9.080 


-413.336 


-318.111 


154.494 


500 


73.330 


86.710 


61.470 


12.620 


-412.743 


-307.559 


134.432 


550 


78.191 


93.929 


64.094 


16.409 


-411.912 


-297.078 


118.047 



Phase changes: 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Wagman (63) after correction for the heat 
of formation of the sulfate ion. The entropy and heat capacity at 298 K are from Papadopoulos 
(47). High-temperature enthalpies were estimated. 



28 



Formation: 



2Cd0-CdS0 4 (c) 
Cadmium oxysulfate 
3Cd(c,l) + S(c,l) + 3 2 (g) = 2Cd0«CdS0 4 (c)] 



T, K 




cal/(mo; 


■•K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H°29 8 )/T 


U° -I u°" 
H u 298 


AHf° 


AGf° 




298.15 


46.126 


58.929 


58.929 





-345.690 


-306.070 


224.352 


300 


46.341 


59.215 


58.928 


.086 


-345.686 


-305.820 


222.787 


368.3 


51.574 


69.256 


59.929 


3.435 


-345.461 


-296.769 


176.101 


368.3 


51.574 


69.256 


59.929 


3.435 


-345.557 


-296.769 


176.101 


388.36 


52.955 


72.034 


60.483 


4.486 


-345.443 


-294.114 


165.511 


388.36 


52.955 


72.034 


60.483 


4.486 


-345.856 


-294.114 


165.511 


400 


53.756 


73.610 


60.843 


5.107 


-345.800 


-292.564 


159.848 


432.02 


55.612 


77.825 


61.945 


6.861 


-345.632 


-288.309 


145.848 


500 


59.053 


86.211 


64.683 


10.764 


-345.265 


-279.310 


122.085 


594.26 


62.373 


96.711 


68.946 


16.499 


-344.422 


-266.947 


98.173 


594.26 


62.373 


96.711 


68.946 


16.499 


-348.862 


-266.948 


98.174 


600 


62.551 


97.311 


69.214 


16.858 


-348.812 


-266.143 


96.941 


700 


64.696 


107.129 


73.945 


23.229 


-347.705 


-252.459 


78.820 


717.82 


64.955 


108.759 


74.789 


24.384 


-347.489 


-250.037 


76.126 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° =» 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° » kcal/mol. 

594.26 K, melting point of Cd; AH° - 1.480 kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 



Sources: The enthalpy of formation at 298 K is from Ko (33) . The entropy 
at 298 K are from Beyer (4), as are the high-temperature enthalpy values. 



and heat capacity 



[Formation: 



2CdO«CdS0 4 (c) 
Cadmium oxysulfate 
3Cd(c,l,g) + 0.5S 2 (g) + 3 2 (g) = 2CdO-CdS0 4 (c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P ° 


S 6 


-(G° - Hi 98 )/T 


TTfO TjO 

11 "298 


AHf° 


AGf° 




298.15 


46.126 


58.929 


58.929 





-361.045 


-315.583 


231.326 


300 


46.341 


59.215 


58.928 


.086 


-361.038 


-315.297 


229.691 


400 


53.756 


73.610 


60.843 


5.107 


-360.451 


-300.130 


163.981 


500 


59.053 


86.211 


64.683 


10.764 


-359.392 


-285.164 


124.643 


594.26 


62.373 


96.711 


68.946 


16.499 


-358.140 


-271.279 


99.766 


594.26 


62.373 


96.711 


68.946 


16.499 


-362.580 


-271.289 


99.766 


600 


62.551 


97.-311 


69.214 


16.858 


-362.507 


-270.384 


98.486 


700 


64.696 


107.129 


73.945 


23.229 


-361.030 


-255.155 


79.662 


800 


66.012 


115.859 


78.648 


29.769 


-359.449 


-240.134 


65.601 


900 


67.098 


123.696 


83.225 


36.424 


-357.806 


-225.307 


54.711 


1,000 


68.630 


130.838 


87.634 


43.204 


-356.081 


-210.670 


46.041 


1,040 


69.723 


133.551 


89.348 


45.971 


-355.347 


-204.895 


43.057 


1,040 


69.723 


133.551 


89.348 


45.971 


-426.774 


-204.895 


43.057 


1,100 


71.362 


137.495 


91.868 


50.190 


-425.230 


-192.136 


38.173 



Phase changes: 



594.26 K, melting point of Cd; AH 
1,040 K, boiling point of Cd; AH° 



=» 1.480 kcal/mol. 
23.809 kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Ko (33) . The entropy and heat capacity 
at 298 K are from Beyer (4), as are the high-temperature enthalpy values. 






29 









Cs 2 SO< 


>(c,l) 














Cesium 


sulfate 












[Formation: 2Cs(c,l) + S(c,l) + 2 2 (g) 


= Cs 2 S0 4 (c,l)] 




T, K 




cal/(moj 


L-K) 


kcal/mol 


Log Kf 




c P u 


S° 


-(G° - H| 98 )/T 


h dogs 


AHf u 


AGf° 
















-6.628 


-342.706 


-342.706 





100 


21.340 


21.970 


75.900 


-5.393 


-344.049 


-335.041 


732.222 


200 


27.430 


38.760 


53.430 


-2.934 


-344.657 


-325.770 


355.980 


298.15 


32.619 


50.640 


50.640 





-344.970 


-316.416 


231.936 


300 


32.697 


50.842 


50.642 


.060 


-344.974 


-316.238 


230.376 


301.55 


32.750 


51.011 


50.643 


.111 


-344.977 


-316.089 


229.084 


301.55 


32.750 


51.011 


50.643 


.111 


-345.977 


-316.089 


229.084 


368.3 


35.014 


57.806 


51.338 


2.382 


-346.046 


-309.465 


183.635 


368.3 


35.014 


57.806 


51.338 


2.382 


-346.142 


-309.465 


183.635 


388.36 


35.695 


59.681 


51.721 


3.091 


-346.143 


-307.467 


173.025 


388.36 


35.695 


59.681 


51.721 


3.091 


-346.556 


-307.467 


173.025 


400 


36.090 


60.741 


51.969 


3.509 


-346.569 


-306.295 


167.350 


432/02 


37.053 


63.557 


52.724 


4.680 


-346.606 


-303.072 


153.315 


500 


39.097 


69.114 


54.580 


7.267 


-346.708 


-296.207 


129.470 


600 


42.455 


76.532 


57.630 


11.341 


-346.485 


-286.119 


104.217 


700 


46.388 


83.363 


60.823 


15.778 


-345.884 


-276.099 


86.201 


717.82 


47.203 


84.539 


61.397 


16.612 


-345.732 


-274.324 


83.520 


Phase ch 


anges : 30 


1.55 K, m« 


siting point of & 


s; AH° - 0.500 kcal/mol. 







368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is from Wagman (6_5) after correction for the heat 
of formation of the sulfate ion. The low-temperature heat capacities are from Paukov (51) , 
while the high-temperature enthalpy values are from Shmidt (56) and Denielou (12); see text. 



30 



[Formation: 



Cs 2 S0 4 (c,l) 
Cesium sulfate 
2Cs(c,l,g) + 0.5S 2 (g) + 2 2 (g) = Cs 2 S0 4 (c,l)] 



T, K 




cal/(moJ 


.•K) 


kcal/mol 


Log Kf 




^F 


S° 


CG* • ii298)/T 


H" - H298 


AHf° 


AGf° 













00 


-6.628 


-358.024 


-358.024 


00 


100 


21.340 


21.970 


75.900 


-5.393 


-359.570 


-348.531 


761.704 


200 


27.430 


38.760 


53.430 


-2.934 


-360.139 


-337.231 


368.504 


299.15 


32.619 


50.640 


50.640 





-360.325 


-325.930 


238.910 


300 


32.697 


50.842 


50.642 


.060 


-360.326 


-325.715 


237.280 


301.55 


32.750 


51.011 


50.643 


.111 


-360.327 


-325.536 


235.931 


301.55 


32.750 


51.011 


50.643 


.111 


-361.327 


-325.536 


235.931 


400 


36.090 


60.741 


51.969 


3.509 


-361.220 


-313.861 


171.483 


500 


39.097 


69.114 


54.580 


7.267 


-360.836 


-302.060 


132.029 


600 


42.455 


76.532 


57.630 


11.341 


-360.180 


-290.360 


105.762 


700 


46.388 


83.363 


60.823 


15.778 


-359.209 


-278.794 


87.042 


800 


50.959 


89.849 


64.049 


20.640 


-357.859 


-267.397 


73.049 


900 


56.175 


96.146 


67.267 


25.991 


-356.053 


-256.192 


62.211 


952 


59.208 


99.380 


68.932 


28.987 


-354.915 


-250.478 


57.501 


952 


59.208 


99.380 


68.932 


28.987 


-387.311 


-250.478 


57.501 


997 


61.832 


103.175 


70.370 


31.710 


-385.981 


-244.040 


53.495 


997 


46.293 


102.248 


70.370 


31.782 


-385.909 


-244.041 


53.495 


1,000 


46.405 


102.387 


70.466 


31.921 


-385.863 


-243.613 


53.241 


1,100 


50.109 


106.984 


73.578 


36.747 


-384.156 


-229.467 


45.590 


1,200 


53.813 


111.502 


76.549 


41.943 


-382.100 


-215.490 


39.246 


1.278 


56.702 


114.981 


78.789 


46.253 


-380.253 


-204.718 


35.008 


1,278 


49.393 


121.609 


78.790 


54.723 


-371.783 


-204.719 


35.008 


1,300 


49.393 


122.452 


79.522 


55.809 


-371.394 


-201.847 


33.933 


1,400 


49.393 


126.112 


82.720 


60.749 


-369.637 


-188.870 


29.484 


1,500 


49.393 


129.520 


85.728 


65.688 


-367.894 


-176.020 


25.646 


1,600 


49.393 


132.708 


88.566 


70.627 


-366.172 


-163.286 


22.303 


1,700 


49.393 


135.702 


91.251 


75.567 


-364.466 


-150.656 


19.368 


1,800 


49.393 


138.526 


93.800 


80.506 


-362.779 


-138.127 


16.771 


1,900 


49.393 


141.196 


96.225 


85.445 


-361.111 


-125.694 


14.458 


2,000 


49.393 


143.730 


98.537 


90.385 


-359.464 


-113.345 


12.386 



Phase changes : 



925 K, calculated boiling point of Cs to ideal monatomic gas; AH° ■ 16.198 

kcal/mol. 
997 K, II-I transition of Cs 2 S0 4 ; AH° = 0.072 kcal/mol. 
1,278 K, melting point of Cs 2 S0 4 ; AH° = 8.47 kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Wagman- (65) after correction for the heat 
of formation of the sulfate ion. The low-temperature heat capacities are from Paukov (51) , 
while the high-temperature enthalpy values are from Shmidt (56) and Denielou (12); see text. 



31 



[Formation: 



In 2 (S0 4 ) 3 (c) 
Indium sulfate 
2In(c,l) + 3S(c,l) + 6 2 (g) = In 2 (S0 4 ) 3 (c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P u 


S° 


-(G° - H5 98 )/T 


TjO TjO" 


AHf° 


AGf° 




298.15 


65.704 


72.240 


72.240 





-651.340 


-570.120 


417.904 


300 


65.972 


72.647 


72.240 


.122 


-651.350 


-569.614 


414.958 


368.3 


73.163 


87.039 


73.665 


4.926 


-651.489 


-550.986 


326.952 


368.3 


73.163 


87.039 


73.665 


4.926 


-651.777 


-550.987 


326.952 


388.36 


75.275 


90.977 


74.460 


6.415 


-651.780 


-545.495 


306.973 


388.36 


75.275 


90.977 


74.460 


6.415 


-653.019 


-545.495 


306.974 


400 


76.501 


93.218 


74.973 


7.298 


-653.062 


-542.272 


296.280 


429.78 


78.510 


98.784 


76.432 


9.606 


-653.170 


-534.020 


271.554 


429.78 


78.510 


98.784 


76.432 


9.606 


-654.730 


-534.020 


271.554 


432.02 


78.661 


99.192 


76.550 


9.782 


-654.768 


-533.391 


269.828 


500 


83.247 


111.051 


80.447 


15.302 


-655.223 


-514.240 


224.771 


600 


88.701 


126.722 


86.880 


23.905 


-655.125 


-486.041 


177.038 


700 


93.716 


140.775 


93.592 


33.028 


-654.470 


-457.905 


142.963 


717.82 


94.595 


143.142 


94.793 


34.706 


-654.297 


-452.902 


137.890 



Phase changes : 368.3 K, orthorhombic-monoclinic transformation of S; AH" = 0.096 kcal/mol. 
388.36 K, melting point of S; AH° = 0.413 kcal/mol. 
429.78 K, melting point of In; AH° = 0.780 kcal/mol. 
432.02 K, second-order transformation of S; AH° = kcal/mol. 
717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is from Barany (2^) after correction for the en- 
thalpy of formation of the sulfate ion. The entropy, heat capacity values, and high-temperature 
enthalpy values at 298 K are from Pankratz (46). 



[Formation: 



In 2 (S0 4 ) 3 (c) 
Indium sulfate 
2In(c,l) + 1.5S 2 (g) + 6 2 (g) = In 2 (S0 4 ) 3 (c) ] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - Hl 98 )/T 


TjO TjO 

H "298 


AHf° 


AGf° 




298.15 


65.704 


72.240 


72.240 





-697.405 


-598.661 


438.825 


300 


65.792 


72.647 


72.240 


.122 


-697.406 


-598.046 


435.671 


400 


76.501 


93.218 


74.973 


7.298 


-697.015 


-564.969 


308.681 


429.78 


78.510 


98.784 


76.432 


9.606 


-696.785 


-555.146 


282.297 


429.78 


78.510 


98.784 


76.432 


9.606 


-698.345 


-555.146 


282.297 


500 


83.247 


111.051 


80.447 


15.302 


-697.606 


-531.800 


232.447 


600 


88.701 


126.722 


86.880 


23.905 


-696.208 


-498.764 


181.672 


700 


93.716 


140.775 


93.592 


33.028 


-694.445 


-465.991 


145.487 


800 


98.648 


153.610 


100.303 


42.646 


-692.318 


-433.500 


118.425 


900 


103.667 


165.518 


106.896 


52.760 


-689.799 


-401.295 


97.446 


1,000 


108.863 


176.707 


113.322 


63.385 


-686.857 


-369.392 


80.730 


1,100 


114.287 


187.335 


119.570 


74.541 


-683.468 


-337.801 


67.114 



Phase changes : 429.78 K, melting point of In; AH C = 0.780 kcal/mol. 

Sources: The enthalpy of formation at 298 K is from Barany (2_) after correction for the en- 
thalpy of formation of the sulfate ion. The entropy, heat capacity values, and high-temperature 
enthalpy values at 298 K. are from Pankratz (46). 



32 



[Formation: 



K 2 S0 4 (c,l) 
Potassium sulfate 
2K(c,l) + S(c,l) + 2 2 (g) = K 2 S0 4 (c,l) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp 4 


S* 


-(G° - H2 98 )/T 


a H 298 


AHf° 


AGf° 













OS 


-6.079 


-341.109 


-341.109 


OO 


100 


18.928 


14.725 


66.295 


-5.157 


-342.567 


-333.760 


729.422 


200 


26.450 


30.436 


44.676 


-2.848 


-343.283 


-324.639 


354.745 


298.15 


31.386 


41.956 


41.956 





-343.620 


-315.406 


231.196 


300 


31.469 


42.150 


41.957 


.058 


-343.624 


-315.230 


229.642 


336.35 


32.858 


45.829 


42.180 


1.227 


-343.711 


-311.786 


202.586 


336.35 


32.858 


45.829 


42.180 


1.227 


-344.827 


-311.786 


202.586 


368.3 


34.078 


48.879 


42.628 


2.303 


-344.877 


-308.645 


183.148 


368.3 


34.078 


48.879 


42.628 


2.303 


-344.973 


-308.645 


183.148 


388.36 


34.844 


50.707 


42.999 


2.994 


-344.992 


-306.665 


172.574 


388.36 


34.844 


50.707 


42.999 


2.994 


-345.405 


-306.665 


172.574 


400 


35.289 


51.743 


43.238 


3.402 


-345.428 


-305.504 


166.917 


432.02 


36.290 


54.499 


43.972 


4.548 


-345.488 


-302.306 


152.928 


500 


38.416 


59.959 


45.779 


7.090 


-345.625 


-295.495 


129.159 


600 


41.235 


67.205 


48.758 


11.068 


-345.466 


-285.477 


103.984 


700 


44.543 


73.812 


51.872 


15.358 


-344.964 


-275.514 


86.018 


717.82 


45.107 


74.939 


52.431 


16.157 


-344.838 


-273.747 


83.345 



Phase changes: 



336.35 K, melting point of K; AH" = 0.558 kcal/mol. 
368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° - 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 



Source: All data are from JANAF (16). 



33 



[Formation: 



K 2 S0 4 (c,l) 
Potassium sulfate 
2K(c,l,g) + 0.5S 2 (g) + 2 2 (g) 



K 2 S0 4 (c,l)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp a 


S° 


-(G° - H 298 )/T 


a u 298 


AHf° 


AGf° 













00 


-6.079 


-356.427 


-356.427 


00 


100 


18.928 


14.725 


66.295 


-5.157 


-358.087 


-347.249 


758.903 


200 


26.450 


30.426 


44.676 


-2.848 


-358.765 


-336.101 


367.269 


298.15 


31.386 


41.956 


41.956 





-358.975 


-324.920 


238.170 


300 


31.469 


42.150 


41.957 


.058 


-358.976 


-324.708 


236.546 


336.35 


32.858 


45.829 


42.180 


1.227 


-359.004 


-320.554 


208.284 


336.35 


32.858 


45.829 


42.180 


1.227 


-360.120 


-320.554 


208.284 


400 


35.289 


51.743 


43.238 


3.402 


-360.079 


-313.070 


171.051 


500 


38.416 


59.959 


45.779 


7.090 


-359.753 


-301.348 


131.718 


600 


41.235 


67.205 


48.758 


11.068 


-359.160 


-289.718 


105.528 


700 


44.543 


73.812 


51.872 


15.358 


-358.289 


-278.209 


86.860 


800 


47.710 


79.966 


55.002 


19.971 


-357.132 


-266.847 


72.898 


857 


49.515 


83.312 


56.775 


22.742 


-356.345 


-260.441 


66.416 


857 


43.977 


85.669 


56.775 


24.762 


-354.325 


-260.441 


66.416 


900 


44.810 


87.842 


58.208 


26.671 


-353.923 


-255.740 


62.101 


1,000 


46.750 


92.663 


61.414 


31.249 


-352.885 


-244.886 


53.519 


1,043.7 


47.602 


94.681 


62.765 


33.311 


-352.387 


-240.175 


50.292 


1,043.7 


47.602 


94.681 


62.765 


33.311 


-390.463 


-240.175 


50.292 


1,100 


48.700 


97.211 


64.465 


36.021 


-389.513 


-232.094 


46.112 


1,200 


50.640 


101.531 


67.374 


40.988 


-387.686 


-217.859 


39.677 


1,300 


52.580 


105.661 


70.162 


46.149 


-385.684 


-203.788 


34.259 


1,342 


53.390 


107.346 


71.299 


48.375 


-384.791 


-197.925 


32.232 


1,342 


48.150 


113.471 


71.299 


56.595 


-376.571 


-197.925 


32.232 


1,400 


48.150 


115.509 


73.090 


59.387 


-375.626 


-190.224 


29.695 


1,500 


48.150 


118.831 


76.030 


64.202 


-374.008 


-177.039 


25.794 


1,600 


48.150 


121.938 


78.802 


69.017 


-372.408 


-163.960 


22.396 


1,700 


48.150 


124.857 


81.426 


73.832 


-370.820 


-150.981 


19.410 


1,800 


48.150 


127.609 


83.916 


78.647 


-369.251 


-138.093 


16.767 


1,900 


48.150 


130.213 


86.286 


83.462 


-367.698 


-125.295 


14.412 


2,000 


48.150 


132.682 


88.544 


88.277 


-366.161 


-112.576 


12.302 



Phase changes 



336.35 K, melting point of K; AH° = 0.558 kcal/mol. 
857 K, cx-6 transition of K 2 S0 4 ; AH° = 2.020 kcal/mol. 
1,043.7 K, calculated boiling point of K to ideal monatomic gas; AH° 
kcal/mol. 
1,342 K, melting point of K 2 S0 4 ; AH° = 8.220 kcal/mol. 



19.038 



Source: All data are from JANAF (16). 



34 



[Formation: 



KAl(S0 4 ) 2 (c) 
Potassium aluminum sulfate 
K(c,l) + Al(c) + 2S(c,l) + 4 2 (g) = KAl(S0 4 ) 2 (c)] 



T, K 




cal/(mo] 


■ •K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H^ 98 )/T 


u h 298 


AHf° 


AGf° 













00 


-7.701 


-585.069 


-585.069 


00 


100 


19.490 


13.860 


82.270 


-6.841 


-587.830 


-571.043 


1,247.998 


200 


35.490 


32.680 


52.850 


-4.034 


-589.655 


-553.484 


604.812 


298.15 


46.141 


48.940 


48.940 





-590.560 


-535.511 


392.535 


300 


46.776 


49.229 


48.942 


.086 


-590.570 


-535.169 


389.865 


336.35 


49.844 


54.754 


49.278 


1.842 


-590.728 


-528.448 


343.365 


336.35 


49.844 


54.754 


49.278 


1.842 


-591.286 


-528.448 


343.365 


368.3 


52.541 


59.526 


49.958 


3.524 


-591.310 


-522.478 


310.035 


368.3 


52.541 


59.526 


49.958 


3.524 


-591.502 


-522.478 


310.035 


388.36 


54.234 


62.359 


50.527 


4.595 


-591.518 


-518.717 


291.904 


388.36 


54.234 


62.359 


50.527 


4.595 


-592.344 


-518.717 


291.905 


400 


55.217 


63.975 


50.895 


5.232 


-592.376 


-516.510 


282.204 


432.02 


56.807 


68.288 


52.026 


7.026 


-592.472 


-510.434 


258.215 


500 


60.184 


76.867 


54.829 


11.019 


-592.754 


-497.493 


217.451 


600 


63.782 


88.171 


59.463 


17.225 


-592.659 


-478.439 


174.269 


700 


66.735 


98.231 


64.297 


23.754 


-592.240 


-459.432 


143.439 


717.82 


67.200 


99.914 


65.160 


24.947 


-592.136 


-456.052 


138.849 



Phase changes: 



= 0.096 kcal/mol. 



336.35 K, melting point of K; AH° = 0.558 kcal/mol. 
368.3 K, orthorhombic-monoclinic transformation of S; AH 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is from Wagman (65) after correction for the sul- 
fate ion. Low-temperature heat capacity and entropy values are from Kelley (30) . High-temper- 
ature enthalpy values are from Kelley (30). 



35 



[Formation: 



KAl(S0 4 ) 2 (c) 
Potassium aluminum sulfate 
K(c,l,g) + Al(c,l) + S 2 (g) + 4 2 (g) = KAl(S0 4 ) 2 (c)] 



T, K 




cal/(mo; 


■•K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - Hl 98 )/T 


no " tjO' 

H u 298 


AHf° 


AGf° 













00 


-7.701 


-615.705 


-615.705 


00 


100 


19.490 


13.860 


82.270 


-6.841 


-618.871 


-598.023 


1,306.961 


200 


35.490 


32.680 


52.850 


-4.034 


-620.620 


-576.407 


629.861 


298.15 


46.141 


48.940 


48.940 


0.000 


-621.270 


-554.538 


406.482 


300 


46.776 


49.229 


48.942 


0.086 


-621.274 


-554.123 


403.673 


336.35 


49.844 


54.754 


49.278 


1.842 


-621.313 


-545.985 


354.760 


336.35 


49.844 


54.754 


49.278 


1.842 


-621.872 


-545.985 


354.760 


400 


55.217 


63.975 


50.895 


5.232 


-621.678 


-531.641 


290.471 


500 


60.184 


76.867 


54.829 


11.019 


-621.009 


-509.199 


222.568 


600 


63.782 


88.171 


59.463 


17.225 


-620.048 


-486.921 


177.359 


700 


66.735 


98.231 


64.297 


23.754 


-618.890 


-464.823 


145.122 


800 


69.343 


107.315 


69.115 


30.560 


-617.578 


-442.905 


120.995 


900 


71.751 


115.623 


73.827 


37.616 


-616.130 


-421.157 


102.269 


933.61 


72.519 


118.268 


75.380 


40.040 


-615.616 


-413.885 


96.886 


933.61 


72.519 


118.268 


75.380 


40.040 


-618.196 


-413.885 


96.886 


1,000 


74.035 


123.302 


78.396 


44.906 


-617.106 


-399.395 


87.287 


1,043.7 


74.998 


126.489 


80.343 


48.162 


-616.351 


-389.896 


81.643 


1,043.7 


74.998 


126.489 


80.343 


48.162 


-635.389 


-389.896 


81.643 


1,100 


76.238 


130.462 


82.807 


52.421 


-634.238 


376.682 


74.839 



Phase changes: 



336.35 K, melting point of K; AH° = 0.558 kcal/mol. 
933.61 K, melting point of Al; AH° = 2.580 kcal/mol. 
1,043.7 K, calculated boiling point of K to ideal monatomic gas; AH C 
kcal/mol. 



= 19.038 



Sources: The enthalpy of formation at 298 K is from Wagman (65) after correction for the sul- 
fate ion. Low-temperature heat capacity and entropy values are from Kelley (30) . High-temper- 
ature enthalpy values are from Kelley (30). 



[Formation: 



KAl(S0 4 ) 2 «12H 2 0(c) 
Potassium aluminum sulfate dodecahydrate 
K(c,l,g) + Al(c,l) + S(c,l) + 12 H 2 (g) + m o 2 (g) = KAl(S0 4 ) 2 -12H 2 0(c)] 



T, K 




cal/(mo; 


■ •K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H° 298 )/T 


no _ rjO 

11 u 298 


AHf° 


AGf° 




298.15 


156.107 


164.300 


164.300 





-1,448.960 


-1,228.988 


900.861 


300 


156.909 


165.268 


164.301 


.290 


-1,449.000 


-1,227.622 


894.311 


336.35 


172.528 


184.094 


165.426 


6.279 


-1,449.477 


-1,200.766 


780.211 


336.35 


172.528 


184.094 


165.426 


6.279 


-1,450.035 


-1,200.766 


780.211 


350 


178.393 


191.074 


166.291 


8.674 


-1,450.082 


-1,190.648 


743.464 


358.99 


182.218 


195.646 


166.968 


10.295 


-1,450.075 


-1,183.983 


720.789 



Phase changes : 336.35 K, melting point of K; AH° = 0.558 kcal/mol. 
358.99 K, melting point of KA1( S0 4 ) 2 - 12H 2 0(c) ; AH° = 

Sources: The enthalpy of formation at 298 K are from Wagmann (65) . 
mate (58) were matched to those of Gronvold (24). 



22.8 kcal/mol. 



Heat capacities from Sho- 



36 



[Formation: 



Li 2 S0 4 (c,l) 
Lithium sulfate 
2Li(c,l) + S(c,l) + 2 2 (g) = Li 2 S0 4 (c,l) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S 6 


-(G° - H| 98 )/T 


» "298 


AHf° 


AGf° 













00 


-4.454 


-340.340 


-340.340 


00 


100 


10.485 


6.915 


46.995 


-4.008 


-341.684 


-333.446 


728.736 


200 


20.763 


17.454 


29.594 


-2.428 


-342.769 


-324.746 


354.861 


298.15 


28.109 


27.234 


27.234 





-343.300 


-315.767 


231.461 


300 


28.209 


27.408 


27.235 


.052 


-343.306 


-315.596 


229.909 


368.3 


31.672 


33.571 


27.846 


2.109 


-343.430 


-309.270 


183.519 


368.3 


31.672 


33.571 


27.846 


2.109 


-343.526 


-309.271 


183.519 


388.36 


32.690 


35.278 


28.186 


2.754 


-343.545 


-307.404 


172.989 


388.36 


32.690 


35.278 


28.186 


2.754 


-343.958 


-307.404 


172.990 


400 


33.280 


36.252 


28.407 


3.138 


-343.982 


-306.308 


167.357 


432.02 


34.446 


38.860 


29.086 


4.222 


-344.058 


-303.295 


153.428 


453.7 


35.235 


40.570 


29.593 


4.981 


-344.179 


-301.244 


145.109 


453.7 


35.235 


40.570 


29.593 


4.981 


-345.613 


-301.244 


145.109 


500 


36.920 


44.076 


30.774 


6.651 


-345.704 


-296.707 


129.689 


600 


40.215 


51.099 


33.584 


10.509 


-345.639 


-286.906 


104.504 


700 


43.450 


57.544 


36.554 


14.693 


-345.211 


-277.149 


86.529 


717.82 


43.997 


58.643 


37.089 


15.472 


-345.097 


-275.417 


83.853 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° ■ 0.096 kcal/mol. 

388.36 K, melting point of S; AH = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° ■ kcal/mol. 

453.7 K, melting point of Li; AH° = 0.717 kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 



Source: All data are from JANAF (17). 



37 



[Formation: 



Li 2 S0 4 (c,l) 
Lithium sulfate 
2Li(c,l,g) + 0.5S 2 (g) + 2 2 (g) = Li 2 S0 4 (c,l)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp u 


S° 


-(G° - Hi 98 )/T 


H° - H 2 98 


AHf° 


AGf° 













00 


-4.454 


-355.658 


-355.658 


00 


100 , 


10.485 


6.915 


46.995 


-4.008 


-357.204 


-346.936 


758.217 


200 


20.763 


17.454 


29.594 


-2.428 


-358.251 


-336.207 


367.386 


298.15 


28.109 


27.234 


27.234 





-358.655 


-325.281 


238.434 


300 


28.209 


27.408 


27.235 


.052 


-358.658 


-325.074 


236.813 


400 


33.280 


36.252 


28.407 


3.138 


-358.633 


-313.874 


171.490 


453.7 


35.235 


40.570 


29.593 


4.981 


-358.522 


-307.874 


148.303 


453.7 


35.235 


40.570 


29.593 


4.981 


-359.956 


-307.874 


148.303 


500 


36.920 


44.076 


30.774 


6.651 


-359.831 


-302.561 


132.247 


600 


40.215 


51.099 


33.584 


10.509 


-359.333 


-291.146 


106.049 


700 


43.450 


57.544 


36.554 


14.693 


-358.536 


-279.844 


87.370 


800 


46.520 


63.531 


39.555 


19.181 


-357.464 


-268.673 


73.397 


848 


48.454 


66.296 


40.991 


21.459 


-356.837 


-263.363 


67.874 


8^8 


51.000 


74.315 


40.991 


28.259 


-350.037 


-263.363 


67.874 


900 


51.000 


77.351 


43.005 


30.911 


-349.183 


-258.075 


62.668 


1,000 


51.000 


82.724 


46.713 


36.011 


-347.561 


-248.038 


54.208 


1,100 


51.000 


87.585 


50.211 


41.111 


-345.962 


-238.162 


47.318 


1,132 


51.000 


89.047 


51.288 


42.743 


-345.455 


-235.033 


45.376 


1,132 


49.000 


90.858 


51.288 


44.793 


-343.405 


-253.033 


45.376 


1,200 


49.000 


93.717 


53.613 


48.125 


-342.471 


-228.552 


41.625 


1,300 


49.000 


97.639 


56.851 


53.025 


-341.110 


-219.115 


36.836 


1,400 


49.000 


101.270 


59.895 


57.925 


-339.767 


-209.781 


32.748 


1,500 


49.000 


104.651 


62.768 


62.825 


-338.434 


-200.545 


29.219 


1,600 


49.000 


107.813 


65.485 


67.725 


-337.116 


-191.393 


26.143 


1,638 


49.000 


108.963 


66.480 


69.587 


-336.617 


-187.939 


25.075 


1,638 


49.000 


108.963 


66.480 


69.587 


-406.937 


-187.940 


25.075 


1,700 


49.000 


110.784 


68.063 


72.625 


-405.905 


-179.665 


23.097 


1,800 


49.000 


113.584 


70.515 


77.525 


-404.247 


-166.402 


20.204 


1,900 


49.000 


116.234 


72.852 


82.425 


-402.607 


-153.237 


17.626 


2,000 


49.000 


118.747 


75.085 


87.325 


-400.979 


-140.151 


15.315 



Phase changes : 



453.7 K, melting point of Li; AH = 0.717 kcal/mol. 
848 K, ct-B transition point for Li 2 S0 4 (c), AH = 6.80 kcal/mol. 
1,132 K, melting point of Li 2 S0 4 (c) , AH° = 2.050 kcal/mol. 
1,638 K, calculated boiling point of Li to ideal monatomic gas; AH e 
kcal/mol. 



= 35.160 



Source: All data from JANAF (17). 



38 



Li 2 S0 4 'H 2 0(c) 
Lithium sulfate monohydrate 





[Formation: 2Li(c,l) + S(c,l) + 


2.5 2 (g) + I 


l 2 (g) = Li 2 S0 4 


•H 2 0(c)] 




T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




■- p B 


S° 


-(G° - H2 98 )/T 


H H 298 


AHf° 


AGf° 













OO 


-5.697 


-409.751 


-409.751 


OO 


100 


13.360 


9.067 


60.217 


-5.115 


-412.023 


-399.526 


873.152 


200 


26.490 


22.512 


38.012 


-3.100 


-413.665 


-386.329 


422.156 


298.'15 


36.100 


34.995 


34.995 





-414.530 


-372.701 


273.194 


300 


36.248 


35.219 


34.996 


.067 


-414.541 


-372.442 


271.320 


350 


39.772 


41.083 


35.452 


1.971 


-414.742 


-365.407 


228.167 


368.3 


40.728 


43.134 


35.783 


2.708 


-414.795 


-362.826 


215.299 


368.3 


40.728 


43.134 


35.783 


2.708 


-414.891 


-362.826 


215.299 


388.36 


41.776 


45.331 


36.218 


3.539 


-414.935 


-359.987 


202.580 


388.36 


41.776 


45.331 


36.218 


3.539 


-415.348 


-359.987 


202.581 


400 


42.384 


46.574 


36.502 


4.029 


-415.389 


-358.327 


195.779 


432.02 


43.473 


49.889 


37.374 


5.407 


-415.511 


-353.761 


178.958 


450 


44.084 


51.674 


37.910 


6.194 


-415.646 


-351.188 


170.558 


453.7 


44.142 


52.035 


38.023 


6.357 


-415.671 


-350.658 


168.912 


453.7 


44.142 


52.035 


38.023 


6.357 


-417.105 


-350.658 


168.912 


500 


44.872 


56.367 


39.523 


8.422 


-417.296 


-343.862 


150.300 


550 


44.748 


60.645 


41.250 


10.667 


-417.490 


-336.507 


133.714 


Phase ch 


anges : 36 


8.3 K, orl 


:hrhomibc-monoclii 


lie transformation of S; AH' 


' = 0.096 kcal/mol. 



388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

453.7 K, melting point of Li; AH° = 0.717 kcal/mol, 

Sources: The enthalpy of formation is based on Barany (3). Low-temperature heat capacities 
and entropies are from Paukov (53). High-temperature enthalpies are estimated. 



39 



[Formation: 



MgS0 4 (6,c,l) 
Magnesium sulfate (8,c,l) 
Mg(c,l,g) + 0.5S 2 (g) + 2 2 (g) = MgS0 4 ($,c,l)] 



T, K 




cal/(mol 


•K) 


kcal/mol 


Log Kf 




Cp* 


S° 


-(G° - H° 298 )/T 


TjO TJO 

H H 298 


AHf° 


AGf u 













00 


-3.678 


-319.706 


-319.706 


00 


100 


8.679 


4.775 


38.315 


-3.354 


-321.290 


-310.932 


679.532 


200 


17.521 


13.751 


23.791 


-2.008 


-322.253 


-300.259 


328.104 


298.15 


23.000 


21.844 


21.844 





-322.465 


-289.302 


212.061 


300 


23.050 


21.987 


21.844 


.043 


-322.466 


-289.094 


210.602 


400 


26.290 


29.085 


22.790 


2.518 


-322.420 


-277.973 


151.875 


500 


28.540 


35.199 


24.675 


5.262 


-322.190 


-266.886 


116.654 


600 


30.500 


40.581 


26.886 


8.217 


-321.835 


-255.853 


93.193 


700 


32.100 


45.404 


29.193 


11.348 


-321.385 


-244.889 


76.457 


800 


33.580 


49.788 


31.497 


14.633 


-320.853 


-234.001 


63.925 


900 


34.950 


53.823 


33.756 


18.060 


-320.245 


-223.175 


54.194 


922 


35.236 


54.671 


34.245 


18.832 


-320.101 


-220.808 


52.339 


922 


35.236 


54.671 


34.245 


18.832 


-322.240 


-220.808 


52.339 


1,000 


36.250 


57.574 


35.953 


21.621 


-321.699 


-212.254 


46.388 


1,100 


37.450 


61.086 


38.081 


25.306 


-320.939 


-201.349 


40.004 


1,200 


38.580 


64.394 


40.136 


29.109 


-320.113 


-190.514 


34.697 


1,300 


39.520 


67.520 


42.123 


33.016 


-319.223 


-179.737 


30.216 


1,363 


40.012 


69.402 


43.341 


35.522 


-318.643 


-173.009 


27.741 


1,363 


40.012 


69.402 


43.341 


35.522 


-348.893 


-173.009 


27.741 


1,400 


40.301 


70.478 


44.044 


37.008 


-348.401 


-168.244 


26.264 


1,400 


38.000 


73.034 


44.044 


40.586 


-344.823 


-168.244 


26.264 


1,500 


38.000 


75.656 


46.065 


44.386 


-343.723 


-155.673 


22.681 


1,600 


38.000 


78.108 


47.992 


48.186 


-342.639 


-143.170 


19.556 


1,700 


38.000 


80.412 


49.832 


51.986 


-341.569 


-130.736 


16.807 


1,800 


38.000 


82.584 


51.592 


55.786 


-340.513 


-118.362 


14.371 


1,900 


38.000 


84.639 


53.278 


59.586 


-339.474 


-106.050 


12.198 


2,000 


38.000 


86.588 


54.895 


63.386 


-338.447 


-93.791 


10.249 



Phase changes 



922 K, melting point of Mg ; AH = 2 . 1 39 kcal/mol . 
1,363 K, boiling point of Mg; AH = 30.250 kcal/mol. 
1,400 K, melting point of MgS0 4 ; AH° = 3.5 kcal/mol. 



Sources: The enthalpy of formation 
All other data are from JANAF (15). 



is based on Ko (34) after correction for the sulfate ion. 



40 



[Formation: 



MgS0 4 (a,c) 
Magnesium sulfate (ot,c) 
Mg(c) + S(c,l) + 2 2 (g) = MgS0 4 (a,c)] 



T, K 


cal/(mol*K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G u - H5 98 )/T 


TjO Tj3 

°- "298 


AHf° 


AGf° 













CO 


-3.678 


-305.308 


-305.308 


OO 


100 


8.679 


4.775 


38.315 


-3.354 


-306.690 


-298.362 


652.061 


200 


17.521 


13.751 


23.791 


-2.008 


-307.691 


-289.718 


316.585 


298.15 


23.000 


21.844 


21.844 





-308.030 


-280.708 


205.762 


300 


23.050 


21.987 


21.844 


.043 


-308.034 


-280.537 


204.369 


368.3 


25.263 


26.957 


22.339 


1.701 


-308.139 


-274.265 


162.747 


368.3 


25.263 


26.957 


22.339 


1.701 


-308.235 


-274.265 


162.747 


388.36 


25.913 


28.314 


22.613 


2.214 


-308.252 


-272.414 


153.299 


388.36 


25.913 


28.314 


22.613 


2.214 


-308.665 


-272.414 


153.299 


400 


26.290 


29.085 


22.790 


2.518 


-308.689 


-271.327 


148.244 


432.02 


27.010 


31.137 


23.334 


3.371 


-308.763 


-268.334 


135.743 


500 


28.540 


35.199 


24.675 


5.262 


-308.983 


-261.953 


114.498 


600 


30.500 


40.581 


26.886 


8.217 


-309.061 


-252.532 


91.984 


700 


32.100 


45.404 


29.193 


11.348 


-308.980 


-243.114 


75.903 


717.82 


32.364 


46.214 


29.605 


11.922 


-308.951 


-241.437 


73,508 



Phase changes 



368.3 K, orthorhombic-monoclinic transformation of S; AH ■ 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 



Sources: The enthalpy of formation is based on Ko ( 34 ) after correction for the sulfate ion. 
All other data are from JANAF (15). 



41 



[Formation: 



MgS0 4 (a,c,l) 
Magnesium sulfate (ct,c,l) 
Mg(c,l,g) + 0.5S 2 (g) + 2 2 (g) = MgS0 4 (a,c,l)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P u 


S° 


-(G u - H$ 98 )/T 


H tt 298 


AHf° 


AGf° 













00 


-3.678 


-320.626 


-320.626 


00 


100 


8.679 


4.775 


38.315 


-3.354 


-322.211 


-311.852 


681.543 


200 


17.521 


13.751 


23.791 


-2.008 


-323.173 


-301.179 


329.109 


298.15 


23.000 


21.844 


21.844 





-323.385 


-290.222 


212.736 


300 


23.050 


21.987 


21.844 


.043 


-323.386 


-290.014 


211.273 


400 


26.290 


29.085 


22.790 


2.518 


-323.340 


-278.893 


152.378 


500 


28.540 


35.199 


24.675 


5.262 


-323.111 


-267.806 


117.057 


600 


30.500 


40.581 


26.886 


8.217 


-322.755 


-256.773 


93.528 


700 


32.100 


45.404 


29.193 


11.348 


-322.305 


-245.809 


76.744 


800 


33.580 


49.788 


31.497 


14.633 


-321.773 


-234.921 


64.177 


900 


34.950 


53.823 


33.756 


18.060 


-321.165 


-224.095 


54.417 


922 


35.236 


54.671 


34.245 


18.832 


-321.021 


-221.728 


52.558 


922 


35.236 


54.671 


34.245 


18.832 


-323.160 


-221.728 


52.558 


1,000 


36.250 


57.574 


35.953 


21.621 


-322.619 


-213.174 


46.589 


1,100 


37.450 


61.086 


38.081 


25.306 


-321.859 


-202.269 


40.187 


1,200 


38.580 


64.394 


40.136 


29.109 


-321.034 


-191.434 


34.864 


1,300 


39.520 


67.520 


42.123 


33.016 


-320.143 


-180.657 


30.371 


1,363 


40.012 


69.402 


43.341 


35.522 


-319.563 


-173.929 


27,888 


1,363 


40.012 


69.402 


43.341 


35.522 


-349.813 


-173.929 


27.888 


1,400 


40.301 


70.478 


44.044 


37.008 


-349.322 


-169.164 


26.407 


1,400 


38.000 


73.034 


44.044 


40.586 


-345.743 


-169.164 


26.407 


1,500 


38.000 


75.656 


46.065 


44.386 


-344.643 


-156.593 


22.815 


1,600 


38.000 


78.108 


47.992 


48.186 


-343.559 


-144.090 


19.682 


1,700 


38.000 


80.412 


49.832 


51.986 


-342.490 


-131.656 


16.925 


1,800 


38.000 


82.584 


51.592 


55.786 


-341.434 


-119.282 


14.483 


1,900 


38.000 


84.639 


53.278 


59.586 


-340.394 


-106.970 


12.304 


2,000 


38.000 


86.588 


54.895 


63.386 


-339.367 


-94.711 


10.349 



Phase changes: 



922 K, melting point of Mg; AH° = 2.139 kcal/mol. 
1,363 K, boiling point of Mg; AH° = 30.250 kcal/mol. 
1,400 K, melting point of MgS0 4 ; AH° = 3.5 kcal/mol. 



Sources: The enthalpy of formation is based on Ko ( 34 ) after correction for the sulfate ion. 
All other data are from JANAF (15). 



42 



MgS0 4 (8,c) 
Magnesium sulfate (g,c) 
[Formation: Mg(c) + S(c,l) + 2 2 (g) = MgS0 4 (B,c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp u 


S° 


-(6" - H5 ga )/T 


a. u 298 


AHf u 


AGf° 
















-3.678 


-304.388 


-304.388 





100 


8.679 


4.775 


38.315 


-3.354 


-305.770 


-297.442 


650.051 


200, 


17.521 


13.751 


23.791 


-2.008 


-306.771 


-288.798 


315.579 


298.15 


23.000 


21.844 


21.844 





-307.110 


-279.788 


205.088 


300 


23.050 


21.987 


21.844 


.043 


-307.114 


-279.617 


203.698 


368.3 


25.263 


26.957 


22.339 


1.701 


-307.219 


-273.345 


162.201 


368.3 


25.263 


26.957 


22.339 


1.701 


-307.315 


-273.345 


162.202 


388.36 


25.913 


28.314 


22.613 


2.214 


-307.332 


-271.494 


152.781 


388.36 


25.913 


28.314 


22.613 


2.214 


-307.745 


-271.494 


152.782 


400 


26.290 


29.085 


22.790 


2.518 


-307.769 


-270.407 


147.742 


432.02 


27.010 


31.137 


23.334 


3.371 


-307.843 


-267.414 


135.278 


500 


28.540 


35.199 


24.675 


5.262 


-308.063 


-261.033 


114.096 


600 


30.500 


40.581 


26.886 


8.217 


-308.141 


-251.612 


91.648 


700 


32.100 


45.404 


29.193 


11.348 


-308.060 


-242.194 


75.615 


717.82 


32.364 


46.214 


29.605 


11.922 


-308.031 


-240.517 


73.228 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH = kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 



Sources: The enthalpy of formation 
All other data are from JANAF (15). 



is based on Ko (34) after correction for the sulfate ion. 



[Formation: 



MgS0 4 -H 2 0(c) 
Magnesium sulfate monohydrate 
Mg(c) + S(c,l) + 2.5 2 (g) + H 2 (g) = MgS0 4 -H 2 0(c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H^ 98 )/T 


a «298 


AHf° 


AGf° 




298.15 


34.600 


30.200 


30.200 





-384.800 


-343.360 


251.686 


300 


34.767 


30.415 


30.202 


.064 


-384.802 


-343.102 


249.946 


350 


39.274 


36.112 


30.641 


1.915 


-384.759 


-336.154 


209.901 


368.3 


40.923 


38.156 


30.964 


2.649 


-384.695 


-333.614 


197.964 


368.3 


40.923 


38.156 


30.964 


2.649 


-384.792 


-333.614 


197.964 


388.36 


42.731 


40.374 


31.391 


3.489 


-384.693 


-330.827 


186.171 


388.36 


42.731 


40.374 


31.391 


3.489 


-385.106 


-330.827 


186.171 


400 


43.780 


41.651 


31.671 


3.992 


-385.053 


-329.201 


179.865 


4332.02 


46.666 


45.132 


32.542 


5.439 


-384.873 


-324.738 


164.276 


450 


48.287 


47.068 


33.084 


6.293 


-384.810 


-322.239 


156.499 


500 


52.794 


52.388 


34.748 


8.820 


-384.328 


-315.309 


137.820 


550 


57.301 


57.631 


36.589 


11.573 


-383.626 


-308.435 


122.559 



Phase changes: 



368.3 K, orthrhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Sources: The enthalpy of formation is based on Ko (34) after correction for the sulfate ion. 
The entropy at 298 K is from Parker (49). The heat capacity estimates are based on Rolla (54). 



43 



[Formation: 



MgS0 4 -2H 2 0(c) 
Magnesium sulfate dihydrate 
Mg(c) + S(c,l) + 3 2 (g) + 2H 2 (g) = MgS0 4 -2H 2 0(c)] 



T, K 


cal/(mol'K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H^ 98 )/T 


TjO tjO 

H "298 


AHf° 


AGf° 




298.15 


42.000 


40.000 


40.000 





-453.300 


-398.172 


291.864 


300 


42.185 


40.260 


40.000 


.078 


-453.308 


-397.828 


289.814 


350 


47.193 


47.139 


40.533 


2.312 


-453.404 


-388.573 


242.633 


368.3 


49.026 


49.591 


40.923 


3.192 


-453.386 


-385.183 


228.566 


368.3 


49.026 


49.591 


40.923 


3.192 


-453.482 


-385.183 


228.566 


388.36 


51.034 


52.244 


41.439 


4.196 


-453.431 


-381.464 


214.666 


388.36 


51.034 


52.244 


41.439 


4.196 


-453.844 


-381.464 


214.666 


400 


52.200 


53.768 


41.776 


4.797 


-453.817 


-379.295 


207.234 


432.02 


55.407 


57.909 


42.818 


6.520 


-453.700 


-373.334 


188.859 


450 


57.208 


60.205 


43.467 


7.532 


-453.670 


-369.992 


179.690 


500 


62.215 


66.492 


45.456 


10.518 


-453.263 


-360.713 


157.665 


550 


67.223 


72.657 


47.650 


13.754 


-452.615 


-351.484 


139.665 



Phase chnages : 



368.3 K, orthrhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Sources: The enthalpy of formation is from Parker ( 49 ) after correction for the sulfate ion. 
The heat capacity and entropy values are estimates. 

MgS0 4 -4H 2 0(c) 
Magnesium sulfate tetrahydrate 
[Formation: Mg(c) + S(c,l) + 4 2 (g) + 4H 2 (g) = MgS0 4 ^H^c) ] 



T, K 




cal/(mo] 


•K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H| 98 )/T 


no tjO 

H H 2g8 


AHf° 


AGf° 




298.15 


60.000 


59.000 


59.000 





-596.800 


-514.117 


376.853 


300 


60.259 


59.372 


59.002 


.111 


-596.814 


-513.603 


374.155 


350 


67.270 


69.187 


59.761 


3 9^ 


^7.001 


-499.717 


312.033 


368.3 


69.836 


72.681 


60.317 


. 


■596.993 


-494. 6 Ju 


293.510 


368.3 


69.836 


72.681 


60.317 


4.554 


-597.089 


-494.630 


293.510 


388.36 


72.648 


76.458 


61.053 


5.983 


-597.036 


-489.050 


275.210 


388.36 


72.648 


76.458 


61.053 


5.983 


-597.449 


-489.050 


275.210 


400 


74.280 


78.628 


61.533 


6.838 


-597.413 


-485.801 


265.426 


432.02 


78.770 


84.518 


63.016 


9.289 


-597.246 


-476.872 


241.236 


450 


81.291 


87.781 


63.941 


10.728 


-597.173 


-471.866 


229.166 


500 


88.301 


69.709 


66.775 


14.967 


-596.580 


-457.972 


200.176 


550 


85.312 


105.454 


69.894 


19.558 


-595.651 


-444.149 


176.486 



Phase changes: 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 

388.36 K, melting point of S; AH° 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol 



0.096 kcal/mol. 



Sources: The enthalpy of formation is from Parker (49) after correction for the sulfate ion. 
The heat capacity and entropy values are estimates. 



44 



[Formation: 



MgS0 4 '6H 2 0(c) 
Magnesium sulfate hexahydrate 
Mg(c) + S(c,l) + 5 2 (g) + 6H 2 (g) 



MgS0 4 -6H 2 0(c) 



T, K 




cal/(mo. 


L-K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H° 298 )/T 


no"" ii°"~~ 
H H 298 


AHf° 


AGf° 













00 


-13.244 


-726.355 


-726.355 


OS 


100 


31.810 


23.110 


141.340 


-11.823 


-733.024 


-699.682 


1,529.135 


200 


61.130 


54.500 


90.120 


-7.124 


-736.624 


-664.853 


726.508 


298.15 


83.200 


83.200 


83.200 





-737.880 


-629.193 


461.205 


300 


83.573 


83.716 


83.203 


.154 


737.890 


-628.518 


457.869 


350 


93.090 


97.327 


84.256 


4.575 


-737.889 


-610.283 


381.073 


368.3 


96.175 


102.150 


85.026 


6.307 


-737.789 


-603.614 


358.181 


368.3 


96.175 


102.150 


85.026 


6.307 


-737.885 


-603.614 


358.181 


388.36 


99.557 


107.351 


86.044 


8.275 


-737.715 


-596.304 


335.566 


388.36 


99.557 


107.351 


86.044 


8.275 


-738.128 


-596.304 


335.566 


400 


101.520 


110.320 


86.708 


9.445 


-738.023 


-592.055 


323.479 


432.02 


106.223 


118.327 


88.756 


12.775 


-737.655 


-580.384 


293.600 


450 


108.864 


122.712 


90.025 


14.709 


-737.470 


-573.845 


278.694 


500 


115.121 


134.516 


93.890 


20.313 


-736.580 


-555.709 


242.897 


550 


120.291 


145.739 


98.097 


26.203 


-735.426 


-537.672 


213.648 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Sources: The enthalpy of formation is from Parker (49) after correction for the sulfate ion. 
The low-temperature heat capacity and entropy values are from Cox (10) , while the high-temper- 
ature enthalpy values are extrapolated. 



[Formation: 



MgS0 4 -7H 2 0(c) 
Magnesium sulfate heptahydrate 
Mg(c) + S(c,l) + 5.5 2 (g) + 7H 2 (g) = MgS0 4 -7H 2 0(c) ] 



T, K 




cal/(mo! 


L-K) 


kcal/mol 


Log Kf 




c P a 


S° 


-(G° - H| 98 )/T 


TjO Tjfl 

"■ H 298 


AHf° 


AGf° 




298.15 


91.000 


89.000 


89.000 


0.000 


-810.000 


-686.432 


503.162 


300 


91.463 


89.564 


89.001 


0.169 


-810.014 


-685.664 


499.500 


350 


103.982 


104.604 


90.161 


5.055 


-810.071 


-644.927 


415.194 


368.3 


108.564 


110.020 


91.014 


7.000 


-809.950 


-657.341 


390.062 


368.3 


108.564 


110.020 


91.014 


7.000 


-810.046 


-657.341 


390.062 


388.36 


113.587 


115.909 


92.147 


9.228 


-809.827 


-649.028 


365.236 


388.36 


113.587 


115.909 


92.147 


9.228 


-810.240 


-649.028 


365.236 


400 


116.501 


119.306 


92.889 


10.567 


-810.089 


-644.199 


351.969 


432.02 


124.518 


128.581 


95.190 


14.426 


-809.533 


-630.939 


319.175 


450 


129.020 


133.750 


96.628 


16.705 


-809.193 


-623.516 


302.817 


500 


141.538 


147.992 


101.054 


23.469 


-807.677 


-602.961 


263.551 


550 


154.057 


162.069 


105.962 


30.859 


-805.560 


-582.583 


231.494 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Sources: The enthalpy of formation and entropy at 298 K are from Parker (49) after correction 
for the sulfate ion. The heat capacity values are estimates based on Rolla (54). 



45 



[Formation: 



Na 2 S0 4 (c) 
Sodium sulfate 
2Na(c,l) + S(c,l) + 2 2 (g) = Na 2 S0 4 (c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P u 


S° 


-(G° - H5 98 )/T 


no _ WO 

a _ 1*298 


AHf° 


AGf° 













00 


-5.549 


-328.959 


-328.959 


00 


100 


15.904 


10.306 


59.036 


-4.873 


-330.475 


-321.789 


703.261 


200 


25.255 


24.620 


38.390 


-2.754 


-331.315 


-312.732 


341.733 


298.15 


30.627 


35.754 


35.754 





-331.696 


-303.517 


222.481 


300 


30.711 


35.944 


35.754 


.057 


-331.699 


-303.340 


220.980 


368.3 


33.422 


42.529 


36.412 


2.253 


-331.819 


-296.872 


176.162 


368.3 


33.422 


42.529 


36.412 


2.253 


-331.915 


-296.872 


176.162 


371 


33.529 


42.773 


36.458 


2.343 


-331.919 


-296.615 


174.729 


371 


33.529 


42.773 


36.458 


2.343 


-333.163 


-296.615 


174.729 


388.36 


34.218 


44.323 


36.776 


2.931 


-333.189 


-294.904 


165.955 


388.36 


34.218 


44.323 


36.776 


2.931 


-333.602 


-294.904 


165.955 


400 


34.680 


45.340 


37.010 


3.332 


-333.632 


-293.744 


160.492 


432.02 


35.766 


48.055 


37.728 


4.461 


-333.709 


-290.548 


146.980 


458 


36.647 


50.169 


38.374 


5.402 


-333.847 


-287.947 


137.402 


458 


36.647 


50.302 


38.374 


5.463 


-333.786 


-287.947 


137.402 


500 


37.980 


53.575 


39.515 


7.030 


-333.815 


-283.742 


124.022 


514 


38.411 


54.630 


39.912 


7.565 


-333.819 


-282.340 


120.048 


514 


40.806 


59.726 


39.912 


10.185 


-331.199 


-282.340 


120.048 


600 


41.905 


66.121 


43.231 


13.734 


-330.920 


-274.192 


99.873 


700 


43.270 


72.682 


46.981 


17.991 


-330.431 


-264.777 


82.666 


717.82 


43.536 


73.773 


47.632 


18.764 


-330.325 


-263.106 


80.105 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

371 K, melting point of Na; AH° = 0.622 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

458 K, V-IV transition of Na 2 S0 4 ; AH° - 0.061 kcal/mol. 

514 K, IV-I transition of Na 2 S0 4 ; AH - 2.607 kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 



Source: All data are from JANAF (16). 



46 



[Formation: 



Na 2 S0 4 (c,l) 
Sodium sulfate 
2Na(c,l,g) + 0.5S 2 (g) + 2 2 (g) = Na 2 S0 4 (c,l)] 



T, K 




cal/(moI 


■ •K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H5 98 )/T 


u ° ZZ u a 
0. ti 2 98 


AHf u 


AGf° 













00 


-5.549 


-344.277 


-344.277 


oa 


100 


15.904 


10.306 


59.036 


-4.873 


-345.996 


-335.279 


732.743 


200 


25.255 


24.620 


38.390 


-2.754 


-346.798 


-324.194 


354.258 


298.15 


30.627 


35.754 


35.754 





-347.051 


-313.031 


229.455 


300 


30.711 


35.944 


35.754 


.057 


-347.051 


-312.818 


227.885 


371 


33.529 


42.773 


36.458 


2.343 


-347.057 


-304.716 


179.500 


371 


33.529 


42.773 


36.458 


2.343 


-348.301 


-304.716 


179.501 


400 


34.680 


45.340 


37.010 


3.332 


-348.283 


-301.309 


164.626 


458 


36.647 


50.169 


38.374 


5.402 


-348.097 


-294.503 


140.530 


458 


36.647 


50.302 


38.374 


5.463 


-347.943 


-294.503 


140.530 


500 


37.980 


53.575 


39.515 


7.030 


-347.943 


-289.595 


126.580 


514 


38.411 


54.630 


39.912 


7.565 


-347.879 


-287.962 


122.438 


514 


40.806 


59.726 


39.911 


10.185 


-345.259 


-287.962 


122.438 


600 


41.905 


66.121 


43.231 


13.734 


-344.615 


-278.433 


101.418 


700 


43.270 


72.682 


46.981 


17.991 


-343.756 


-267.472 


83.507 


800 


44.760 


78.556 


50.566 


22.392 


-342.777 


-256.639 


70.110 


900 


46.330 


83.919 


53.978 


26.947 


-341.670 


-245.937 


59.721 


1,000 


47.875 


88.880 


57.223 


31.657 


-340.437 


-235.365 


51.438 


1,100 


49.410 


93.515 


60.313 


36.522 


-339.090 


-224.923 


44.687 


1,157 


50.279 


96.033 


62.005 


39.370 


-338.259 


-219.012 


41.369 


1,157 


47.092 


100.960 


62.006 


45.070 


-332.559 


-219.012 


41.369 


1,177 


47.092 


101.767 


62.675 


46.012 


-332.331 


-217.052 


40.302 


1,177 


47.092 


101.767 


62.675 


46.012 


-378.901 


-217.052 


40.302 


1,200 


47.092 


102.678 


63.438 


47.088 


-378.552 


-213.903 


38.957 


1,300 


47.092 


106.448 


66.604 


51.797 


-377.002 


-200.242 


33.663 


1,400 


47.092 


109.938 


69.577 


56.506 


-375.474 


-186.705 


29.146 


1,500 


47.092 


113.187 


72.377 


61.215 


-373.961 


-173.278 


25.246 


1,600 


47.092 


116.226 


75.023 


65.925 


-372.464 


-159.946 


21.847 


1,700 


47.092 


119.081 


77.532 


70.634 


-370.983 


-146.709 


18.860 


1,800 


47.092 


121.773 


79.916 


75.343 


-369.516 


-133.558 


16.216 


1,900 


47.092 


124.319 


82.186 


80.052 


-368.064 


-120.489 


13.859 


2,000 


47.092 


126.734 


84.354 


84.761 


-366.626 


-107.495 


11.746 



Phase changes : 371 K, melting point of Na; AH° = 0.622 kcal/mol. 



AH = 0.061 kcal/mol. 
AH = 2.607 kcal/mol. 
AH° = 5.700 kcal/mol. 
1,177 K, boiling point of Na to ideal monatomic gas; AH 

Source: All data re from JANAF (16). 



458 K, V-IV transition of Na 2 S0 4 
514 K, IV-I transition of Na 2 S0 4 
1,157 K, melting point of Na 2 S0 4 



23.285 kcal/mol. 



47 



[Formation: 



Na 2 SO 4 '10H 2 O(c) 
Sodium sulfate decahydrate 
2Na(c,l) + S(c,l) + 10H 2 (g) + 7 2 (g) = Na 2 S0 4 -10H 2 0(c) ] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H° 298 )/T 


TjO ~ TTO 

H. H 298 


AHf° 


AGf^ 




298.15 


124.000 


141.500 


141.500 





-1,034.240 


-871.491 


638.812 


300 


124.666 


142.269 


141.502 


.230 


-1,034.265 


-870.480 


634.136 


350 


142.666 


162.838 


143.087 


6.913 


-1,034.487 


-843.154 


526.482 


368.3 


149.254 


170.277 


144.254 


9.584 


-1,034.373 


-833.152 


494.387 


368.3 


149.254 


170.277 


144.254 


9.584 


-1,034.469 


-833.152 


494.388 


371 


150.226 


171.371 


144.448 


9.988 


-1,034.444 


-831.677 


489.920 


371 


150.226 


171.371 


144.448 


9.988 


-1,035.688 


-831.677 


489.921 


388.36 


156.476 


178.381 


145.805 


12.651 


-1,035.468 


-822.133 


462.650 


388.36 


156.476 


178.381 


145.805 


12.651 


-1,035.881 


-822.133 


462.650 


400 


160.666 


183.064 


146.822 


14.497 


-1,035.696 


-815.729 


445.688 


432.02 


172.193 


195.874 


149.983 


19.826 


-1,034.966 


-798.147 


403.761 


450 


178.666 


203.027 


151.960 


22.980 


-1,034.477 


-788.302 


382.847 


500 


196.666 


222.783 


158.057 


32.363 


-1,032.356 


-761.054 


332.652 


550 


214.666 


242.371 


164.831 


42.647 


-1,029.352 


-734.062 


291.685 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

371 K, melting point of Na; AH° = 0.622 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

Source: The enthalpy of formation and entropy at 298 K are from Wagman ( 65 ) after the sulfate 
correction. Heat capacity values are estimated. 



[Formation: 



(NH 4 ) 2 S0 4 (c) 
Ammonium sulfate 
N 2 (g) + 4H 2 (g) + S(c,l) + 2 2 (g) = (NH 4 ) 2 S0 4 (c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H 298 )/T 


nO ' ttO 

11 tt 298 


AHf° 


AGf° 













OO 


-8.512 


-275.800 


-275.800 


00 


100 


19.024 


13.672 


90.382 


-7.671 


-280.072 


-259.425 


566.965 


200 


43.996 


33.445 


56.875 


-4.686 


-282.144 


-237.807 


259.860 


298.15 


44.812 


52.710 


52.710 





-282.660 


-216.006 


158.335 


300 


44.936 


52.988 


52.711 


.083 


-282.678 


-215.593 


157.057 


368.3 


49.349 


62.645 


53.673 


3.304 


-283.175 


-200.261 


118.834 


368.3 


49.349 


62.645 


53.673 


3.304 


-283.271 


-200.261 


118.834 


388.36 


50.645 


65.297 


54.207 


4.307 


-283.373 


-195.736 


110.149 


388.36 


50.645 


65.297 


54.207 


4.307 


-283.786 


-195.737 


110.149 


400 


51.397 


66.804 


54.552 


4.901 


-283.853 


-193.097 


105.502 


432.02 


53.567 


70.845 


55.611 


6.581 


-284.017 


-185.826 


94.004 


500 


58.173 


78.988 


58.240 


10.374 


-284.278 


-170.348 


74.458 


600 


65.745 


90.250 


62.647 


16.562 


-283.970 


-147.579 


53.755 


650 


69.886 


95.674 


64.979 


19.952 


-283.522 


-136.229 


45.804 



Phase changes 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH = kcal/mol. 



Sources: The enthalpy of formation at 298 K is from Parker (50) after correction for the SO^" 
ion. The entropy at 298 K is based on Kelley (30) . Low-temperature heat capacity values and 
high-temperature enthalpies are from Kelley (30); see text. 



48 



NH 4 Al(S0 4 ) 2 (c) 
Ammonium aluminum sulfate 
[Formation: 0.5N 2 (g) + 2H 2 (g) + Al(c,l) + 2S(c) + 4 2 (g) = NH 4 A1(S0 4 ) 2 (c) ] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(6° - H° 298 )/T 


tjO 7Tb 

H - H 298 


AHf° 


AGf° 













oo 


-8.620 


-554.437 


-554.437 


00 


100 


20.215 


11.852 


90.282 


-7.843 


-558.648 


-535.793 


1,170.959 


200 


40.973 


32.717 


56.282 


-4.713 


-561.166 


-511.855 


559.322 


298.15 


54.114 


51.715 


51.715 





-562.400 


-487.355 


357.236 


300 


54.315 


52.050 


51.717 


.100 


-562.416 


-486.889 


354.694 


368.3 


61.840 


64.370 


52.916 


4.218 


-562.586 


-469.661 


278.694 


368.3 


61.840 


64.370 


52.916 


4.218 


-562.778 


-469.661 


278.694 


388.36 


64.051 


67.710 


53.596 


5.481 


-562.799 


-464.588 


261.444 


388.36 


64.051 


67.710 


53.596 


5.481 


-563.625 


-464.588 


261.444 


400 


65.333 


69.620 


54.035 


6.234 


-563.656 


-461.620 


252.214 


432.02 


66.768 


74.706 


55.381 


8.349 


-563.750 


-453.449 


229.388 


500 


69.816 


84.730 


58.700 


13.015 


-564.047 


-436.059 


190.599 


600 


72.512 


97.714 


64.147 


20.140 


-564.063 


-410.454 


149.506 


650 


73.552 


103.560 


66.957 


23.792 


-563.985 


-397.656 


133.702 



Phase changes: 



368.3 K, orthrhombic-monocTinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 



Source: See text. 



[Formation: 



NH 4 Al(S0 4 ) 2 «12H 2 0(c) 
Ammonium aluminum sulfate dodecahydrate 
0.5N 2 (g) + 14H 2 (g) + Al(c) + 10 2 (g) = NH 4 A1(S0 4 ) 2 -12H 2 0(c) ] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp 6 


S° 


-CG° - Hi 98 )/T 


TjO Tj6" 

11 "298 


AHf° 


AGf° 




298.15 


162.962 


166.600 


166.600 





-1,420.420 


-1,180.311 


865.180 


300 


163.740 


167.610 


166.603 


.302 


-1,420.468 


-1,178.821 


858.759 


350 


183.761 


194.379 


168.670 


8.998 


-1,421.170 


-1,138.476 


710.887 


367.13 


190.175 


203.313 


170.080 


12.201 


-1,421.212 


-1,124.638 


669.480 



Phase changes : 367.13 K, melting point of NH 4 A1(S0 4 ) 2 «12H 2 0(c) ; AH° - 29.16 kcal/mol, 

Sources: The enthalpy of formation and entropy at 298 K are from Wagman (63) after correction 
for the sulfate ion. Heat capacity values are from Kelley (30) and Gronvold (24). 



49 



[Formation: 



PbS0 4 (c) 
Lead sulfate 
Pb(c,l) + S(c,l) + 2 2 (g) = PbS0 4 (c) 



T, K 


cal/(mol*K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H 298 )/T 


TjO TjO 

H u 2?8 


AHf° 


AGf° 













00 


-4.792 


-217.814 


-217.814 


00 


100 


14.408 


14.516 


54.396 


-3.988 


-218.985 


-210.978 


461.086 


200 


20.356 


26.492 


37.632 


-2.228 


-220.849 


-203.936 


222.848 


298.15 


24.667 


35.490 


35.490 





-219.870 


-194.327 


142.444 


300 


24.717 


35.636 


35.489 


.044 


-219.874 


-194.168 


141.449 


368.3 


25.502 


40.612 


35.992 


1.702 


-220.003 


-188.302 


111.737 


368.3 


25.502 


40.612 


35.992 


1.702 


-220.099 


-188.302 


111.737 


388.36 


25.733 


41.971 


36.266 


2.216 


-220.121 


-186.569 


104.990 


388.36 


25.733 


41.971 


36.266 


2.216 


-220.534 


-186.569 


104.990 


400 


25.867 


42.733 


36.443 


2.516 


-220.565 


-185.551 


101.379 


432.02 


26.674 


44.756 


36.985 


3.357 


-220.660 


-182.745 


92.445 


500 


28.388 


48.772 


38.318 


5.227 


-220.918 


-176.754 


77.258 


600 


31.033 


54.180 


40.518 


8.197 


-221.008 


-167.910 


61.161 


600.65 


31.051 


54.214 


40.533 


8.217 


-221.007 


-167.851 


61.073 


600.65 


31.051 


54.214 


40.533 


8.217 


-222.154 


-167.851 


61.073 


600 


33.735 


59.167 


42.831 


11.435 


-221.999 


-158.879 


49.604 


717.82 


34.222 


60.021 


43.247 


12.040 


-221.941 


-157.273 


47.883 



Phase changes : 



368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

600.65 K, melting point of Pb; AH° » 1.147 kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 



Sources: The enthalpy of formation and entropy at 298 K are from CODATA (7) . Low-temperature 
heat capacity values are from Gallagher ( 21 ) , while high-temperature enthalpy values are from 
Krestovnikov (35). 



[Formation: 



PbS0 4 (c) 
Lead sulfate 
Pb(c,l) + 0.5S 2 (g) + 2 2 (g) = PbS0 4 (c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




c P ° 


S° 


-(G° - H2 98 )/T 


tt "298 


AHf° 


AGf° 













OO 


-4.792 


-233.132 


-233.132 


OO 


100 


14.408 


14.516 


54.396 


-3.988 


-234.506 


-224.468 


490.568 


200 


20.356 


26.492 


37.632 


-2.228 


-236.331 


-215.397 


235.372 


298.15 


24.667 


35.490 


35.490 





-235.225 


-203.841 


149.417 


300 


24.717 


35.636 


35.489 


.044 


-235.226 


-203.645 


148.353 


400 


25.867 


42.733 


36.443 


2.516 


-235.216 


-193.116 


105.512 


500 


28.388 


48.772 


38.318 


5.227 


-235.045 


-182.608 


79.817 


600 


31.033 


54.180 


40.518 


8.197 


-234.702 


-172.151 


62.705 


600.65 


31.051 


54.214 


40.533 


8.217 


-234.699 


-172.082 


62.612 


600.65 


31.051 


54.214 


40.533 


8.217 


-235.846 


-172.081 


62.612 


700 


33.735 


59.167 


42.831 


11.435 


-235.324 


-161.574 


50.445 


800 


36.469 


63.849 


45.168 


14.945 


-234.570 


-151.086 


41.274 


900 


39.220 


68.304 


47.493 


18.730 


-233.564 


-140.707 


34.168 


1,000 


41.983 


72.579 


49.789 


22.790 


-232.308 


-130.459 


28.511 


1,100 


44.753 


76.710 


52.049 


27.127 


-230.796 


-120.350 


23.911 



Phase changes: 600.65 K, melting point of Pb; AH° = 1.147 kcal/mol. 



Sources: The enthalpy of formation and entropy at 298 K are from CODATA (_7 ) . Low-temperature 
heat capacity values are from Gallagher (21) , while high-temperature enthalpy values are from 
Krestovnikov (35). 



50 



[Formation: 



Rb 2 S0 4 (c) 
Rubidium sulfate 
2Rb(c,l) + S(c,l) + 2 2 (g) = Rb 2 S0 4 (c) 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H$ 98 )/T 


TjO TjO 


AHf° 


AGf° 




298.15 


32.011 


47.190 


47.190 





-343.120 


-314.742 


230.709 


300 


32.087 


47.388 


47.191 


.059 


-343.125 


-314.566 


229.158 


312.64 


32.539 


48.722 


47.226 


.467 


-343.156 


-313.362 


219.051 


312.64 


32.539 


48.722 


47.226 


.467 


-344.204 


-313.362 


219.051 


368.3 


34.529 


54.238 


47.873 


2.344 


-344.331 


-307.855 


182.679 


368.3 


34.529 


54.238 


47.873 


2.344 


-344.427 


-307.855 


182.680 


388.36 


35.247 


56.089 


48.250 


3.044 


-344.452 


-305.862 


172.122 


388.36 


35.247 


56.089 


48.250 


3.044 


-344.865 


-305.862 


172.122 


400 


35.663 


57.136 


48.494 


3.457 


-344.891 


-304.693 


166.474 


432.02 


36.610 


59.919 


49.239 


4.614 


-344.960 


-301.473 


152.507 


500 


38.619 


65.405 


51.069 


7.168 


-345.115 


-294.617 


128.775 


600 


41.692 


72.719 


54.079 


11.184 


-344.940 


-284.527 


103.637 


700 


45.230 


79.394 


57.224 


15.519 


-344.391 


-274.495 


85.700 


717.82 


46.496 


80.547 


57.789 


16.336 


-344.243 


-272.717 


83.031 



Phase changes : 



312.64 K, melting point of Rb; AH° = 0.524 kcal/mol. 

368.3 K, orthorhombic-monoclinic transformation of S; AH = 0.096 kcal/mol. 

388.36 K, melting point of S; AH° = 0.413 kcal/mol. 

432.02 K, second-order transformation of S; AH° = kcal/mol. 

717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is from CODATA (_7). The entropy at 298 K was 
calculated by Paukov (52) . Low-temperature heat capacities are from Paukov (52). High-temper- 
ature enthalpies are from Denielou (13). See text for high-temperature discussion. 



51 



[Formation: 



Rb 2 S0 4 (c,l) 
Rubidium sulfate 
2Rb(c,l,g) + 0.5S 2 (g) + 2 2 (g) = Rb 2 S0 4 (c,l)] 



T, K 




cal/(mo] 


■ •K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H! 98 )/T 


H° - H 2 9 8 


AHf° 


AGf° 




298.15 


32.011 


47.190 


47.190 





-358.475 


-324.255 


237.683 


300 


32.087 


47.388 


47.191 


.059 


-358.477 


-324.043 


236.062 


312.64 


32.539 


48.722 


47.226 


.467 


-358.488 


-322.592 


225.504 


312.64 


32.539 


48.722 


47.226 


.467 


-359.536 


-322.592 


225.504 


400 


35.663 


57.136 


48.494 


3.457 


-359.542 


-312.259 


170.608 


500 


38.619 


65.405 


51.069 


7.168 


-359.242 


-300.470 


131.334 


600 


41.692 


72.719 


54.079 


11.184 


-358.635 


-288.768 


105.182 


700 


45.230 


79.394 


57.224 


15.519 


-357.716 


-277.190 


86.541 


800 


52.335 


85.828 


60.397 


20.345 


-356.319 


-265.774 


72.605 


900 


69.840 


92.855 


63.602 


26.328 


-353.784 


-254.577 


61.819 


931 


78.971 


95.367 


64.616 


28.629 


-352.558 


-251.180 


58.963 


931 


43.881 


95.479 


64.616 


28.733 


-352.454 


-251.180 


58.963 


974.5 


45.053 


97.509 


66.040 


30.667 


-352.035 


-246.465 


55.274 


974.5 


45.053 


97.509 


66.040 


30.667 


-386.495 


-246.465 


55.274 


1,000 


45.740 


98.682 


66.857 


31.825 


-386.129 


-242.806 


53.065 


1,100 


48.435 


103.168 


69.955 


36.534 


-384.539 


-228.547 


45.408 


1,200 


51.129 


107.498 


72.905 


41.512 


-382.703 


-214.446 


39.056 


1,300 


53.824 


111.697 


75.729 


46.759 


-380.614 


-200.507 


33.708 


1,339 


54.874 


113.303 


76.799 


48.879 


-379.732 


-195.116 


31.846 


1,339 


49.335 


120.203 


76.799 


58.059 


-370.552 


-195.116 


31.846 


1,400 


49.335 


122.401 


78.780 


61.069 


-369.484 


-187.210 


29.224 


1,500 


49.335 


125.805 


81.804 


66.002 


-367.748 


-174.253 


25.388 


1,600 


49.335 


128.989 


84.655 


70.935 


-366.030 


-161.411 


22.047 


1,700 


49.335 


131.980 


87.351 


75.869 


-364.326 


-148.673 


19.113 


1,800 


49.335 


134.800 


89.910 


80.802 


-362.637 


-136.034 


16.517 


1,900 


49.335 


137.467 


92.343 


85 736 


-360.966 


-123. 4 C - 


14.205 


2,000 


49.335 


139.998 


94.664 


90.66b 


-359.314 


-111.039 


12.134 



Phase changes: 



312.64 K, melting point of Rb; AH° = 0.524 kcal/mol. 
931 K, transition for Rb 2 S0 4 ; AH° = 0.104 kcal/mol. 

974.5 K, calculated boiling point of Rb fn ideal monatomic gas; AH e 
kcal/mol. 
1,339 K, melting point of Rb 2 S0 4 ; 9.18 kcal/mol. 



= 17.230 



Sources: The enthalpy of formation is from CODATA (7 ) . The entropy at 298 K was calculated 
by Paukov (52) . Low-temperature heat capacities are from Paukov (52) . High-temperature en- 
thalpies are from Denielou (13). See text for high-temperature discussion. 



52 



[Formation: 



Tl 2 S0 4 (c) 
Thallium sulfate 
2Tl(c,l) + S(c,l) + 2 2 (g) = Tl 2 S0 4 (c)] 



T, K 


cal/(mol*K) 


kcal/mol 


Log Kf 




c P a 


S° 


-(G° - H^ 98 )/T 


ti. tt 298 


AHf° 


AGf° 




298.15 


32.045 


55.100 


55.100 





-322.800 


-198.575 


145.558 


300 


32.151 


55.299 


55.102 


.059 


-222.801 


-198.425 


144.551 


368.3 


35.664 


62.263 


55.794 


2.383 


-222.696 


-192.884 


114.456 


368.3 


35.664 


62.263 


55.794 


2.383 


-222.792 


-192.884 


114.456 


388.36 


36.695 


64.182 


56.179 


3.108 


-222.733 


-191.257 


107.628 


388.36 


36.695 


64.182 


56.179 


3.108 


-223.146 


-191.257 


107.628 


400 


37.294 


65.275 


56.428 


3.539 


-223.123 


-190.301 


103.975 


432.02 


38.753 


68.203 


57.193 


4.757 


-223.057 


-187.677 


94.941 


500 


41.852 


74.092 


59.094 


7.499 


-222.916 


-182.113 


79.600 


507 


42.155 


74.676 


59.305 


7.793 


-222.889 


-181.541 


78.255 


507 


42.155 


74.676 


59.305 


7.793 


-223.069 


-181.541 


78.255 


577 


45.185 


80.322 


61.516 


10.851 


-222.750 


-175.822 


66.595 


577 


45.185 


80.322 


61.516 


10.851 


-224.730 


-175.822 


66.595 


600 


46.181 


82.108 


62.271 


11.902 


-224.548 


-173.879 


63.335 


700 


50.400 


89.544 


65.641 


16.732 


-223.494 


-165.503 


51.672 


717.82 


51.143 


90.820 


66.250 


17.637 


-223.261 


-164.029 


49.940 



Phase changes: 368.3 K, orthorhombic-monoclinic transformation of S; AH° = 0.906 kcal/mol. 
388.36 K, melting point of S; AH° = 0.413 kcal/mol. 
432.02 K, second-order transformation of S; AH° = kcal/mol. 
507 K, ct-B transition point of Tl; AH° = 0.090 kcal/mol. 
577 K, melting point of Tl; AH = 0.990 kcal/mol. 
717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation after correction for the heat of formation of the sulfate 
ion and entropy at 298 K are from Wagman (63). High-temperature heat capacities are from Shmidt 
( 57 ) and are matched with high-temperature enthalpy values of Dworkin (19). 



53 



[Formation: 



Tl 2 S0 4 (c,l) 
Thallium sulfate 
2Tl(c,l) + 0.5S 2 (g) + 2 2 (g) = Tl 2 S0 4 (c,l)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-<G- - H| 9a )/T 


TjO TjO 

a tt 29 8 


AHf° 


AGf° 




298.15 


32.045 


55.100 


55.100 


' 


-238.155 


-208.089 


152.531 


300 


32.151 


55.299 


55.102 


.059 


-238.153 


-207.902 


151.455 


400 


37.294 


65.275 


56.428 


3.539 


-237.774 


-197.867 


108.108 


500 


41.852 


74.092 


59.094 


7.499 


-237.044 


-187.966 


82.159 


507 


42.155 


74.676 


59.305 


7.793 


-236.983 


-187.278 


80.728 


507 


42.155 


74.676 


50.305 


7.793 


-237.163 


-187.278 


80.728 


577 


45.185 


80.322 


61.516 


10.851 


-236.538 


-180.427 


68.339 


577 


45.185 


80.322 


61.516 


10.851 


-238.518 


-180.427 


68.339 


600 


46.181 


82.108 


62.271 


11.902 


-238.243 


-178.120 


64.879 


700 


50.400 


89.544 


65.641 


16.732 


-236.819 


-168.198 


52.513 


774 


53.484 


94.762 


68.178 


20.576 


-235.526 


-161.023 


45.467 


774 


45.949 


94.968 


68.178 


20.736 


-235.366 


-161.023 


45.467 


800 


45.238 


96.473 


69.073 


21.920 


-235.083 


-158.530 


43.308 


900 


48.210 


101.894 


72.421 


26.526 


-233.965 


-149.018 


36.186 


916 


49.358 


102.754 


72.944 


27.306 


-233.745 


-147.511 


35.194 


916 


40.000 


109.162 


72.944 


33.176 


-227.876 


-147.511 


35.194 


1,000 


40.000 


112.672 


76.136 


36.536 


-227.472 


-140.156 


30.631 



Phase changes: 



507 K, a-g transition point of Tl; AH = 07090 kcal/mol. 
577 K, melting point of Tl; AH° = 0.990 kcal/mol. 
774 K, orthorhombic to hexagonal transition for Tl 2 S0 4 (c), AH C 
kcal/mol. 
916 K, melting point of Tl 2 S0 4 (c); AH° - 5.870 kcal/mol. 



= 0.160 



Sources: The enthalpy of formation after correction for the heat of formation of the sulfate 
ion and entropy at 298 K are from Wagman ( 63 ) . High-temperature heat capacities are from Shmidt 
(57) and are matched with high-temperature enthalpy values of Dworkin (19). 



[Formation: 



Zr(S0 4 ) 2 (c) 
Zirconium sulfate 
Zr(c) + 2S(c,l) + 4 2 (g) = Zr(S0 4 ) 2 (c)] 



T, K 


cal/(mol«K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H| 98 )/T 


TjO TjO 

H h 298 


AHf° 


AGf° 




298.15 


37.828 


31.800 


31.800 





-536.200 


-479.891 


351.765 


300 


38.183 


32.035 


31.802 


.070 


-536.213 


-479.540 


349.340 


368.3 


46.142 


40.942 


32.661 


3.050 


-536.367 


-466.610 


276.884 


368.3 


46.142 


40.942 


32.661 


3.050 


-536.559 


-466.610 


276.884 


388.36 


48.480 


43.452 


33.156 


3.999 


-536.552 


-462.799 


260.437 


388.36 


48.480 


43.452 


33.156 


3.999 


-537.378 


-462.799 


260.437 


400 


49.836 


44.904 


33.477 


4.571 


-537.392 


-460.564 


251.637 


432.02 


51.162 


48.793 


34.469 


6.188 


-537.438 


-454.414 


229.875 


500 


53.978 


56.550 


36.954 


9.798 


-537.630 


-441.324 


192.900 


600 


55.165 


66.525 


41.073 


15.271 


-537.583 


-422.064 


153.735 


700 


54.955 


75.025 


45.332 


20.785 


-537.494 


-402.818 


125.764 


717.82 


54.785 


76.404 


46.086 


21.763 


-537.483 


-399.389 


121.598 



Phase changes : 368.3 K, orthorhombic-monoclinic transformation of S";~ AH° = "0.096" kcal/moT. 
388.36 K, melting point of S; AH° = 0.413 kcal/mol. 
432.02 K, second-order transformation of S; AH° = kcal/mol. 
717.824 K, boiling point of S to equilibrium mixture of S n (n = 1 to 8). 

Sources: The enthalpy of formation at 298 K is based on Melnikova (43). The entropy at 298 K 
was estimated by Stern (61). High-temperature enthalpy values are from Shmidt (60). 



54 



[Formation: 



Zr(S0 4 ) 2 (c) 
Zirconium sulfate 
Zr(c) + S 2 (g) + 4 2 (g) 



Zr(S0 4 ) 2 (c)] 



T, K 




cal/(mo] 


■ •K) 


kcal/mol 


Log Kf 




Cp° 


S° 


-(G° - H° 298 )/T 


H "298 


AHf° 


AGf a 




298.15 


37.828 


31.800 


31.800 





-566.910 


-498.918 


365.712 


300 


38.183 


32.035 


31.802 


.070 


-566.917 


-498.495 


363.149 


400 


49.836 


44.904 


33.477 


4.571 


-566.694 


-475.696 


259.905 


500' 


53.978 


56.550 


36.954 


9.798 


-565.885 


-453.031 


198.017 


600 


55.165 


66.525 


41.073 


15.271 


-564.972 


-430.546 


156.824 


700 


54.955 


75.025 


45.332 


20.785 


-564.144 


-408.209 


127.447 


800 


54.001 


82.308 


49.512 


26.237 


-563.490 


-385.984 


105.445 


900 


52.615 


88.591 


53.512 


31.571 


-563.046 


-363.823 


88.347 


1,000 


50.961 


94.051 


57.299 


36.752 


-562.835 


-341.701 


74.678 


1,050 


50.063 


96.516 


59.109 


39.277 


-565.355 


-319.528 


63.484 



Sources: The enthalpy of formation at 298 K is based on Melnikova (43) . The entropy at 298 K 
was estimated by Stern (61). High-temperature enthalpy values are from Smith (60). 



55 



REFERENCES 

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59 



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